Commonwealth of Australia v Snell

BETWEEN: COMMONWEALTH OF AUSTRALIA Appellant

JUDGES: ALLSOP CJ, REEVES AND DERRINGTON JJ DATE OF ORDER: 11 APRIL 2019

1. The appeal be allowed.
2. The decision of the Administrative Appeals Tribunal dated 2 May 2018 be set aside.
3. The matter be remitted to the Administrative Appeals Tribunal for determination according to law and in accordance with these reasons.
4. The parties be heard as to costs. Note: Entry of orders is dealt with in Rule 39.32 of the Federal Court Rules 2011.

Introduction 1 This appeal concerns the operation of the compensation provisions of the Seafarers Rehabilitation and Compensation Act 1992 (Cth) (the Seafarers Act) as applied by the Administrative Appeals Tribunal (the Tribunal) when conducting a review of an employer's decision. Specifically, the question raised is whether, when exercising the powers of the employer in the course of a review, the Tribunal is constrained in the evidence it might consider by reason of an earlier decision by it on the same issue between the same parties. The resolution of this question requires a consideration of the interaction of the powers exercised by the Tribunal under the Seafarers Act and the Tribunal's powers of review in the Administrative Appeals Tribunal Act 1975 (Cth) (the AAT Act). 2 The context in which the issue arises is the Commonwealth's appeal, pursuant to s 44 of the AAT Act, from a decision of the Tribunal made on 2 May 2018 which set aside the Commonwealth's reviewable decision to the effect it was not liable to pay compensation to the respondent, Mr Patrick Snell, in response to his claim under the Seafarers Act. Mr Snell had sought compensation for metastatic malignant melanoma which he claims was contributed to in a material degree by his employment. For the purposes of the Seafarers Act, the Commonwealth stood in the stead of his erstwhile employer for the purposes of satisfying any liability. 3 The Commonwealth asserted that Mr Snell's employment had not contributed to his present medical condition. It sought to adduce expert evidence to the effect that his sun exposure as a child was the cause of his existing condition rather than his exposure during employment. That evidence can be taken to be for the purposes of this appeal persuasive, significant and relevant. It went to the heart of the issues of causation and liability in the decision under review. The Tribunal, however, declined to consider it because it concluded Mr Snell's present condition was the same condition as, or derived from, a solar induced skin disease which, in 2013, it had determined had been contributed to in a material degree by Mr Snell's employment. In reaching its conclusion not to allow the issue of whether Mr Snell's employment as a seafarer contributed to his present condition to be re-litigated, the Tribunal applied a principle which it regarded as being analogous to issue estoppel. In the application of that principle, it imposed upon the Commonwealth the obligation of establishing some good reason why the causation issue should be reconsidered. 4 The principle applied was inappropriately restrictive given the scheme of the AAT Act and the Seafarers Act, in particular s 43(6) and s 78 of those Acts, respectively. The scheme of the legislation is to provide for the administration of claims, including the review of determinations by the Tribunal, including where appropriate the reconsideration of earlier determinations. No principle of issue estoppel or some cognate procedural rule of approach, taken from procedure and principle governing final hearings of judicial or quasi-judicial tribunals, should restrict what is to be drawn from the statute: a progressive and evolving decision-making giving effect to the ongoing review of entitlements including, where appropriate, the review of earlier determinations. Where, as here, material is brought forward in an apparently genuine way that may lead to a reconsideration of an earlier determination as incorrect, it would be wrong to prevent the consideration of factual matters relevant to the making of the preferable decision by reference to such a principle drawn from judicial or quasi-judicial hearings the purpose of which is the determination of matters finally. The Tribunal erred in applying an approach which was inconsistent with the content of the legislative regime, in particular s 43(6) of the AAT Act and s 78 of the Seafarers Act. 5 Although it may be that, had the Tribunal applied the correct principle and considered the merits of the application by evaluating all of the available relevant evidence, it may have reached the same conclusion which it actually did, it is apparent that in rejecting the evidence it applied an erroneous principle and the matter must now be remitted to it for further hearing.

The facts 6 The foundation of Mr Snell's claim is that he worked as a seafarer, including with the entity Australian National Line (ANL) and its successor entities, from 1957 to 1994 and during that period he was regularly exposed to the sun. There were no recorded histories of him suffering from sunburn during that period, but it can be accepted that his self-diagnosis that he avoided any such injury might well be subjective. 7 In the period from March 2000 to July 2016 Mr Snell suffered various solar related medical conditions and underwent several medical procedures including the removal of a number of malignant melanomas. 8 On 29 June 2011 he made a claim under the Seafarers Act for compensation for "solar induced skin disease". He also made a claim for permanent impairment for "solar induced malignant skin disease". The basis of his claim was that these conditions were contributed to in a material degree by his employment with ANL. The Commonwealth did not accept liability for Mr Snell's claim and he sought review of its decision by the Tribunal. 9 Mr Snell and the Commonwealth engaged in the usual preparatory processes for having Mr Snell's claim determined by the Tribunal. Medical reports, witness statements and statutory declarations were obtained and exchanged between the parties. A brief consideration of the medical evidence is necessary to identify the scope of the issues which were agitated between them. 10 A report from a dermatologist, Dr Wagner, of 13 June 2011, identified the extent of the skin damage sustained by Mr Snell. It recorded that he had certain malignant melanomas removed and that further excisions would be required. Dr Wagner opined that Mr Snell's workplace sun exposure contributed in a material degree to his conditions. He noted: Whether Mr Snell is likely to develop new lesions in the future is highly probable given his past history demonstrating prolonged periods of occupational exposure to the sun. 11 On 7 June 2012, Dr James Muir, also a dermatologist, provided a medico-legal report in relation to Mr Snell's skin disease. After listing the extensive malignancies treated surgically over the years, he identified that Mr Snell had two high risk malignancies in 2004 and 2005. He said of these: Both of these lesions are high risk, however there has been a very significant period of time since their removal and the risk of local or systemic recurrence becomes less. 12 Dr Muir also opined that the cause of Mr Snell's skin condition was his exposure to sun during the course of his employment although did acknowledge that skin damage is cumulative over time. Later in his report he said: His loss of life expectancy is difficult to calculate. The reason for this is that he has had two very significant malignant melanomas as outlined above. However these lesions were treated over seven years ago and thus his chances of having further problems with these is greatly reduced with the passage of time. It is not impossible but is now much less likely that these lesions will recur either locally or systemically. The other malignant melanomas that he had were level 1 lesions and can be considered cured. As he is now 77 years old his life expectancy regardless of his skin malignancies is likely less then [sic] 20 years at the outside. An assessment of his life expectancy based on his overall state of health is outside my area of expertise. According to the published survival tables for melanoma, the 3.9 mm thick malignant melanoma excised from his thigh in 2004 with no evidence of nodal disease would have had a 5 year survival rate of 67.4% and a ten year survival rate of 53.9%. As stated above most recurrences of melanomas occur within ten years of excision. According to the melanoma guidelines 80% occur within the first three years. Thus it is now much more likely than not that Mr Snell will not develop recurrence of his invasive melanomas and thus these lesion [sic] are now very unlikely to result in any loss of life expectancy. Thus using table B4 one would have to award of score of 0 at this stage. Once again there is still a chance that these invasive melanomas could recur in which case his loss of life expectancy would be greater. 13 It is patent that the issues which were alive between the parties in this first Tribunal proceeding included both the cause of the solar induced skin disease and the risk that the melanomas which had been removed, or thought to have been removed, would recur either locally or systemically or would metastasise and cause cancer in other parts of Mr Snell's body. 14 This initial proceeding before the Tribunal was resolved by agreement and a consent order made by the Tribunal on 2 April 2013 pursuant to s 42C of the AAT Act (the 2013 decision). Relevantly, the Tribunal's decision recorded as follows: (a) the applicant's solar induced skin disease has been contributed to in a material degree by his employment with the respondent; (b) the respondent has accepted liability for the applicant's solar induced skin disease under the Seafarers Rehabilitation and Compensation Act 1992 ("the SRC Act"); (c) as a result of his solar induced skin disease the applicant has suffered a 10% whole person impairment under s39 of the SRC Act as assessed pursuant to Tables 4.1, 4.2 and 4.3 of the Second Edition of the Guide to the Assessment of the Degree of Permanent Impairment and is therefore entitled to compensation of $16,860.50; and (d) in addition, the applicant is entitled to compensation of $13,139.50 under s41 of the SRC Act for non-economic loss. 15 It does not appear to be in contention that by agreeing to the terms of the consent order the Commonwealth was prepared to accept liability for the skin disease which included the malignant melanomas which had been excised. That included an acceptance that Mr Snell's employment with ANL had contributed in a material degree to the solar induced skin disease then being experienced by him. Necessarily, it also included an acceptance of liability in respect of the future crystallisation of any risk that the melanomas would recur either locally or systemically, even though that risk was not significant.

The second diagnosis 16 In about July 2016, Mr Snell was diagnosed with metastatic malignant melanoma, a terminal cancer. He asserts that this condition was also contributed to in a material degree by his service with ANL and, indeed, he says it is the manifestation of one of the malignant melanomas for which liability was accepted in the 2013 decision. Accordingly, on 22 January 2017 he lodged a second claim for permanent impairment compensation for solar induced skin disease under the Seafarers Act. 17 On 6 February 2017, the Commonwealth obtained a report from a Professor Fox who opined that Mr Snell's employment over approximately 40 years as a seafarer was not responsible for the onset of the metastatic malignant melanoma. In that report Professor Fox provided a partial record of a consultation with Mr Snell in which he says Mr Snell said words to the effect that he had not suffered sunburn whilst working as a seafarer and that the only occasions on which he had been sunburnt was during his childhood. Professor Fox referenced some recent scientific publications and research concerning the effect of outdoor occupational exposure to sun on the development of malignant melanoma. In relation to a study carried out by the Cancer Epidemiology and Services Research Centre at the Sydney School of Public Health, he said: There has been an important, recent study carried out by the Cancer Epidemiology and Services Research Centre at the Sydney School of Public Health in the University of Sydney. They have published a paper titled "Occupational sun exposure and risk of melanoma according to anatomical site" (International J, Cancer, 2014). The authors of this are Vuong K et al. They note that "although sunburn and intermittent sun exposures, are associated with increased melanoma risk most studies have found null or inverse associations between occupational (more continuous pattern) sun exposure and melanoma risk. The associations of melanoma with occupational sun exposure may differ according to anatomical site and some studies finding a positive association with melanoma on the head and neck. They examined the association between occupational sun exposure (self-reported weekday sun exposure) and melanoma risk according to site. They used the data from two multicentre population-based case-control studies - The Australian Melanoma Family Study (588 cases and 472 controls) and the Genes, Environment and Melanoma Study (GEM, 1079 cases and 2181 controls). Unconditional logistic regression was used to estimate odds ratio and their 95% confident intervals adjusting for potential confounders. Occupational sun exposure was not positively associated with melanoma risk overall at different body sites in both studies. The GEM study found inverse association between occupational sun exposure and melanoma on the head and neck and between the proportion of total sun exposure occurring on weekdays and melanoma on the upper limbs. The concluded that this study suggest that occupational sun exposure does not increase the risk of melanoma, even if melanoma situated on the head and neck. There are many other studies showing occupational ie constant exposure is not related to melanoma causation, as distinct from intermittent, recreational exposure. (Elwood JM et al, International J Cancer, 1985). 18 There is nothing in the material to suggest that Professor's Fox's report was not cogent, substantive evidence relevant to the issue of the cause of Mr Snell's malignant melanoma. 19 The contrary opinions as to the cause of Mr Snell's condition were contained in the reports of Drs Wagner and Muir which linked prolonged sun exposure over a person's adult working life to the onset of metastatic malignant melanoma. 20 On 2 March 2017 the Commonwealth determined to refuse liability to pay compensation in response to the second claim. It affirmed that decision by way of a reviewable decision made under s 78(2) of the Seafarers Act on 22 May 2017. 21 Mr Snell lodged an application to the Tribunal for review of the reviewable decision on 24 May 2017.

The Tribunal's decision 22 As mentioned above, the Tribunal did not engage in any substantive assessment of whether the malignant melanomas which were excised prior to the 2013 decision had been contributed to in a material degree by Mr Snell's employment with ANL. It determined that no reason had been shown why the issue of what had caused Mr Snell's conditions should be re-litigated given that it had been determined by the 2013 decision. 23 The reasons of the Tribunal can be summarised as follows: (a) The Tribunal was satisfied that Mr Snell suffered from metastatic malignant melanoma which was a terminal cancer. (b) It identified that it had to be satisfied that Mr Snell's employment contributed in a material degree to his contraction of metastatic malignant melanoma. (c) It accepted that on 2 April 2013, Mr Snell had previously obtained compensation for "solar induced skin disease", payable by the Commonwealth (in the stead of Australian River Co Ltd) and the foundation of that conclusion was that Mr Snell's "solar induced skin disease" had been contributed to in a material degree by his employment. (d) It observed that Mr Snell had submitted that his current condition of metastatic malignant melanoma is a subset, or natural consequence of the "solar induced skin disease" for which the Commonwealth had accepted liability. The Commonwealth submitted to the contrary. (e) The Tribunal accepted Mr Snell's submissions. At paragraph [22] of its reasons it found in relation to the cause of Mr Snell's current condition: I find that the possibility of one of the litany of skin cancers and conditions from which the Applicant was suffering at the time of the 2013 decision transforming or metastasising into metastatic malignant melanoma was both squarely within the contemplation of the parties and of the Tribunal at the time of the 2013 decision. Further, I am satisfied on the balance of probabilities that that is what occurred. And later at [34]: I therefore find, on the balance of probabilities, that the cause or progenitor of the Applicant's present metastatic malignant melanoma was one of the malignant melanomas which were excised from him in the period 2004-2011, and which were all covered by the expression "solar induced skin disease" as used in the 2013 decision. (f) The Tribunal found that the metastatic malignant melanoma was caused by one of the melanomas which Mr Snell had excised in the period from 2004 to 2011 and in respect of which the Commonwealth had accepted liability. Those melanomas were the subject of the 2013 decision and part of the "solar induced skin disease". It rejected the proposition that the present condition was caused by a later melanoma from which Mr Snell had suffered (the 2015 melanoma). (g) The Tribunal then determined that the metastatic malignant melanoma was not a secondary condition in the sense referred to in Canute. It was the consequence of the cells of one of the melanoma which had been excised migrating in the body to the lymph nodes and then spreading. That being so the present condition was not a separate condition from the original solar induced skin disease and Mr Snell was still suffering from the malignant melanomas which were compensated for by the 2013 decision. (h) The Tribunal then considered whether it should reconsider the cause of the occurrence of skin conditions which were the subject of the 2013 decision. That is, whether they had been contributed to in a material degree by his employment or, as Professor Fox opined, by reason of Mr Snell's exposure to sun in his childhood. (i) The Tribunal concluded it had power to refuse to reconsider an issue which had been previously determined by it in relation to a claim. In doing so it relied upon s 33 of the AAT Act and the principles identified in a decision of the Tribunal in Re Matusko and Australian Postal Corporation (1995) 21 AAR 9 (Matusko) which decided that, although the Tribunal it was not bound by issue estoppel, it was able to regulate the re-litigation of issues already determined. It considered that it should commence with the presumption that matters should not be allowed to be re-litigated. (j) The circumstances in which the Tribunal might allow re-litigation of a point already determined were identified in Matusko as being: (i) where there is a different decision; (ii) where there is a clear legislative intent; (iii) where the reconsideration decision is not final; (iv) where there has been a change in circumstances or fresh evidence; or (v) where justice to the parties requires a departure from the general rule. (k) However, the Tribunal determined that the mere fact that the decision before it was different to the 2013 decision did not warrant re-consideration of the previously decided causation issue. It also confined the application of the decision in Telstra Corporation Ltd v Hannaford (2006) 151 FCR 253 at [57] to circumstances where there exists a discontinuity between the applicant's existing symptoms and those for which liability has been previously determined or where there has been a change in the functional effect of the injury. It further found there was a legislative intent in the Seafarers Act which pointed away from the re-litigation of issues which have previously been determined. (l) The central issue considered by the Tribunal in this respect was whether there had been a change in the circumstances or fresh evidence, being Professor Fox's report, a recent study by a Dr Vuong on sun exposure and a change in Mr Snell's evidence to the effect that he had not suffered sunburn whilst at sea. It was concluded that Professor Fox's report could have been acquired for the original proceedings by the use of reasonable diligence and that weighed against re-opening the question of liability. Whilst the Vuong study was only produced after the 2013 decision, its conclusions were not novel and the same view could previously have been advanced. It also found that Mr Snell's statement to Professor Fox that he had not been sunburnt whilst at sea, which was contrary to his assertions prior to the 2013 decision, was evidence which could have been obtained by the respondent earlier and was not sufficiently strong to justify the re-agitation of the causation issue. Taking these matters together, the Tribunal concluded that there was no justification for allowing re-litigation, and that was particularly so in circumstances where Mr Snell's condition had deteriorated significantly as a result of the same condition. (m) On that basis the Tribunal determined not to reconsider the cause of the original condition such that it necessarily followed that it was compelled to find that the metastatic malignant melanoma was contributed to in a material degree by Mr Snell's employment and loss was calculated accordingly.

The legislative scheme 24 The general imposition of liability of an employer to pay compensation to an injured employee is effected by s 24 of the Seafarers Act as follows: 24 Liability to pay compensation The liability of an employer to pay compensation to a person under this Act is the liability of the employer to pay the amount or amounts that the employer determines, in accordance with this Act, to be payable to the person. The determination to be made "in accordance with this Act" is central to the Act's operation, as can be seen from the provisions discussed in paragraph [30] below. 25 The general entitlement of a seafarer to compensation for an injury is found in s 26: 26 Compensation for injuries (1) If an employee suffers an injury that results in his or her death, incapacity for work, or impairment, compensation is payable for the injury. 26 An employee's specific entitlement to compensation for an injury resulting in permanent impairment is found in s 39: 39 Compensation for injuries resulting in permanent impairment (1) If an injury to an employee results in a permanent impairment, compensation is payable to the employee for the injury. 27 That section further provides that the amount of compensation payable is determined by the employer who is obliged to determine whether the impairment (as defined in s 3) is permanent: s 39(2); and assess the degree of permanent impairment as a percentage: s 39(5) and (6). The monetary sum of the amount of compensation is obtained by applying that percentage to a statutorily prescribed figure: s 39(3), (4) and (9), having regard to the inclusions and exclusions specified: s 39(7) and (8). 28 By s 40, if an employer is satisfied the degree of impairment is equal to or greater than 10% but has not yet made a final determination, the employer is obliged upon a written request to make an interim determination of the degree of permanent impairment following which an amount of compensation will be paid. By s 40(3) provision is made for the payment of additional amounts consequent upon a final determination. Sub-section (4) concerns those situations where, after a final assessment is made, the employee suffers a subsequent increase in the degree of impairment from the injuries. It provides: (4) If a final assessment is made of the degree of permanent impairment of an employee, no further amounts of compensation are payable to the employee in respect of a subsequent increase in the degree of impairment, unless the increase is 10% or more. 29 By s 41 a similar methodology is applied to the liability to pay additional compensation for non-economic loss. 30 Section 63 provides that compensation is not payable to a person unless a claim for compensation is made pursuant to that section. In determining the claim made the employer is entitled to require medical examinations (s 66) and the provision of information and documents (s 67) despite, in the case of medical reports, the existence of legal professional privilege (s 70). The employer is required to determine the claim within specified time limits (ss 72, 73 and 73A). The variety of occasions on which the employer is called upon in the Act to make a determination for the various kinds of compensation available is reflected by the definition of "determination" in s 76. 31 Part 6 of the Seafarers Act deals with reconsideration of determinations by employers. Section 77 obliges the employer who has made a determination to serve on the claimant a notice in writing of that determination. Section 78 provides: (1) An employer may, on the employer's own initiative, reconsider a determination made by the employer, whether or not a proceeding has been instituted or completed under this Part in respect of a reviewable decision made in relation to that determination. (2) A claimant may, by notice in writing given to an employer, request the employer to reconsider a determination made by the employer. … (6) After an employer reconsiders a determination, the employer must make a decision affirming or revoking the determination or varying the determination in such manner as the employer thinks fit. 32 The term "reviewable decision" is defined in s 76(1) as "a decision made under section 78". An employee may apply to the Tribunal for review of a "reviewable decision": s 88(1). 33 It follows that an employer is liable to pay compensation for an injury suffered by an employee which results in permanent impairment. The extent of the obligation to pay is dependent upon the assessment of the degree of permanent impairment made by the employer. However, it is apparent that the Seafarers Act does not operate in a once-and-for-all manner in relation to the employee's entitlement to compensation. Sections such as s 40(4) unambiguously disclose that it is contemplated that a final assessment of an employee's level of impairment arising from an injury may well be subsequently reviewed where the impairment increases with the consequence that a further entitlement to compensation will arise. Necessarily that requires the decision-maker to be satisfied that the subsequently increased degree of impairment was the consequence of the compensable injury. 34 The flexible nature of the compensatory scheme in cognate legislation, being the Safety, Rehabilitation and Compensation Act 1988 (Cth) (the SRC Act), was identified by the Full Court in Telstra Corporation Ltd v Hannaford (2006) 151 FCR 253 at [57] (Hannaford), which is discussed below. 35 Also relevant to the questions on appeal are certain provisions of the AAT Act, which apply subject to modification by s 89 of the Seafarers Act. 36 By s 25 of the AAT Act it is provided that other enactments may confer on the Tribunal jurisdiction to hear reviews of decisions made under those enactments. That is the primary source of the Tribunal's jurisdiction to undertake reviews. Where that jurisdiction is conferred, s 43 affords the Tribunal the ability to exercise the powers of decision-makers under those enactments. It also provides that the Tribunal's decision on review is deemed to be the decision of the original decision-maker. Relevantly, s 43 provides: Tribunal's decision on review (1) For the purpose of reviewing a decision, the Tribunal may exercise all the powers and discretions that are conferred by any relevant enactment on the person who made the decision and shall make a decision in writing: (a) affirming the decision under review; (b) varying the decision under review; or (c) setting aside the decision under review and: (i) making a decision in substitution for the decision so set aside; or (ii) remitting the matter for reconsideration in accordance with any directions or recommendations of the Tribunal. … (6) A decision of a person as varied by the Tribunal, or a decision made by the Tribunal in substitution for the decision of a person, shall, for all purposes (other than the purposes of applications to the Tribunal for a review or of appeals in accordance with section 44), be deemed to be a decision of that person and, upon the coming into operation of the decision of the Tribunal, unless the Tribunal otherwise orders, has effect, or shall be deemed to have had effect, on and from the day on which the decision under review has or had effect. 37 This section is important in the resolution of the present matter where the Seafarers Act confers on the employer the power to reconsider, on its own initiative, a previous determination made by it. That being so, when the Tribunal on review effectively stands in the stead of the employer, it exercises the power of a decision-maker who is entitled to reconsider its own decisions. 38 The power of the Tribunal to remit the matter for reconsideration by the original decision-maker reinforces the legal reality that the Tribunal is merely acting in an administrative capacity and, even when it makes a decision in substitution for the decision which it sets aside, that decision is deemed for all purposes to be the decision of the decision-maker: s 43(6) of the AAT Act. 39 Sections 33(1) and 42B of the AAT Act afford the Tribunal the power to control aspects of its procedure and the manner in which it informs itself: 33 Procedure of Tribunal (1) In a proceeding before the Tribunal: (a) the procedure of the Tribunal is, subject to this Act and the regulations and to any other enactment, within the discretion of the Tribunal; (b) the proceeding shall be conducted with as little formality and technicality, and with as much expedition, as the requirements of this Act and of every other relevant enactment and a proper consideration of the matters before the Tribunal permit; and (c) the Tribunal is not bound by the rules of evidence but may inform itself on any matter in such manner as it thinks appropriate. … 42B Power of Tribunal if a proceeding is frivolous, vexatious etc. (1) The Tribunal may dismiss an application for the review of a decision, at any stage of the proceeding, if the Tribunal is satisfied that the application: (a) is frivolous, vexatious, misconceived or lacking in substance; or (b) has no reasonable prospect of success; or (c) is otherwise an abuse of the process of the Tribunal. …

The Tribunal, issue estoppel and fresh evidence 40 The central question on appeal concerns the entitlement of the Tribunal when reviewing a decision to refuse to consider cogent, persuasive and relevant evidence on the basis that the issue to which the evidence relates had been determined by it in the course of the making of an earlier decision. Here, the Tribunal refused to consider evidence which may have established the injury or disease in respect of which compensation was claimed had not been contributed to in a material degree by Mr Snell's employment. Had that evidence been considered and accepted, it may have demonstrated that the 2013 decision, to which the parties had consented under s 42C, was founded upon a false premise.

Can a decision of the Tribunal give rise to an issue estoppel? 41 Although it was not the subject of direct, fulsome submissions during the course of the appeal, it is appropriate to consider whether a decision of the Tribunal can give rise to an issue estoppel. The answer to that assists in ascertaining whether any principles akin to issue estoppel might alternatively apply. 42 Issue estoppel is one reflection of a "central and pervading tenet of the judicial system… that controversies, once resolved, are not to be reopened except in a few, narrowly defined, circumstances": D'Orta-Ekenaike v Victoria Legal Aid (2005) 223 CLR 1, 17 [34]. However, the Tribunal is not a part of the judicial system, and nor can it be: Constitution Ch III. That said, in Administration of the Territory of Papua New Guinea v Daera Guba (1973) 130 CLR 353 (Daera Guba) it was said by Gibbs J at 453: The use of the phrase "judicial tribunal" in this context is convenient as indicating that an estoppel of this kind does not result from a mere administrative decision, but the question whether such an estoppel is raised is not answered by inquiring to what extent the tribunal exercises judicial functions, or whether its status is judicial or administrative … The doctrine of estoppel extends to the decision of any tribunal which has jurisdiction to decide finally a question arising between parties, even if it is not called a court, and its jurisdiction is derived from statute or from the submission of parties, and it only has temporary authority to decide a matter ad hoc. (citations omitted) 43 That statement and his Honour's broader analysis of the estoppel point was agreed to by Menzies and Stephen JJ. Barwick CJ (with whom McTiernan J agreed) expressed slightly different but not inconsistent views at 402-404. The latter half of the statement above was not disapproved when it was regarded as "common ground" in Kuligowski v Metrobus (2004) 220 CLR 363 (Metrobus) at 373-4. These authorities identify the touchstone of issue estoppel as being located in the finality of the decision which results from a judicial or adjudicative process between parties. 44 Given the above, the next question is: can the doctrine apply in the Tribunal? More precisely, it is whether the Tribunal's decision on review has the necessary quality of finality flowing from an adjudicative process to attract an issue estoppel if the same point is raised between the same parties in subsequent proceedings. The starting point is the nature of the Tribunal and the AAT Act. Unlike many tribunals, the Tribunal's power is derivative upon the power of the decision-makers from whose decisions applications for review can be made. In that respect it is most unlike the Land Board which was the subject of consideration in Daera Guba. Importantly, the AAT Act expressly provides that the Tribunal's decision is deemed "for all purposes" to be that of the original decision-maker: s 43(6), whose decision is, of course, a "mere administrative decision". The Tribunal is not to be overly formal or technical: s 33(1)(b) and nor it is it to be bound by the rules of evidence: s 33(1)(c). Those s 33 provisions have been said by the Full Court to exclude the doctrine of issue estoppel: Minister for Immigration and Ethnic Affairs v Daniele (1981) 61 FLR 354 at 359 per Fisher and Lockhart JJ: Issue estoppel, generally but not universally seen as a rule of evidence, cannot have any place in proceedings of the Tribunal and is, to the extent that it is a rule of evidence, expressly excluded by the provisions of s 33 of the Administrative Appeals Tribunal Act. 45 It might be said that at least the latter part of that statement is now eclipsed by the shift in recognition of the status of the doctrine from a rule of evidence to a rule of law: see eg Queensland v Commonwealth (1977) 139 CLR 585 at 615 per Aickin J; Spencer Bower & Handley on Res Judicata (4th ed, LexisNexis, 2009), [1.07]. Perhaps relevantly, however, at the time s 33(1)(c) was enacted, the doctrine was understood to be a 'rule of evidence': Spencer Bower & Turner on Res Judicata (2nd ed, Butterworths, 1969), p 9; Daera Guba at 453 per Gibbs J citing Carl Zeiss Stiftung v Rayner & Keeler Ltd (No 2) [1967] 1 AC 853 (Carl Zeiss) at 933. 46 In Metrobus at 373 [21], the High Court unanimously adopted Lord Guest's statement in Carl Zeiss at 935 of the requirements of issue estoppel: (1) that the same question has been decided; (2) that the judicial decision which is said to create the estoppel was final; and, (3) that the parties to the judicial decision or their privies were the same persons as the parties to the proceedings in which the estoppel is raised or their privies. 47 Given that identification of the elements of issue estoppel, an essential question is whether a decision of the Tribunal is "judicial in the relevant sense": Spencer Bower & Handley on Res Judicata (4th ed, LexisNexis, 2009), Ch 2. 48 Although the express terms of the AAT Act are the first consideration, the second reading speech (Australia, House of Representatives, Parliamentary Debates (1975) Vol HR93, p 1187) might be thought to give some guidance where it was said: … the Tribunal is not to be an ordinary court, but neither is it to be an appendage of Government departments. The Tribunal is to be regarded as machinery provided by Parliament for adjudication rather than as part of the machinery of departmental administration. Nothing less than a tribunal of full judicial status would be satisfactory for these purposes. 49 Given the potentially very broad implications of that statement it is appropriate to set out more fully the observations of Gibbs J in Daera Guba: On behalf of the applicants a number of submissions were urged in support of the contention that even if the Board were validly constituted its decision did not create an estoppel. In the course of these submissions, two misconceptions became manifest. In the first place, some of the applicants' arguments rested on the supposition that the Administration in the present case is endeavouring to set up an issue estoppel. The contention of the Administration is that the Board decided one of the very questions that falls for decision in the present case - whether the Administration is the owner of areas nos 2, 3 and 4 on plan "J" - and not that the Board's decision estops the Tubumaga from relitigating issues which were necessarily determined in reaching that decision. In other words, the present case is one of cause of action estoppel, not issue estoppel. Secondly, much attention was directed to authorities that deal with the nature of judicial power, for example in relation to Ch III of the Constitution. In many of the authorities that discuss this form of estoppel, it is said that the estoppel is brought about by a judicial decision, pronounced by a judicial tribunal. Thus in a recent case, Carl Zeiss Stiftung v Rayner & Keeler Ltd [No 2], Lord Guest said: "The rule of estoppel by res judicata, which is a rule of evidence, is that where a final decision has been pronounced by a judicial tribunal of competent jurisdiction over the parties to and the subject-matter of the litigation, any party or privy to such litigation as against any other party or privy is estopped in any subsequent litigation from disputing or questioning such decision on the merits (Spencer Bower on Res Judicata, p 3)." The use of the phrase "judicial tribunal" in this context is convenient as indicating that an estoppel of this kind does not result from a mere administrative decision, but the question whether such an estoppel is raised is not answered by inquiring to what extent the tribunal exercises judicial functions, or whether its status is judicial or administrative. A fairly obvious example is the case of a court-martial, whose sentence might in some circumstances be pleaded as an estoppel, although not made in the exercise of judicial power. The doctrine of estoppel extends to the decision of any tribunal which has jurisdiction to decide finally a question arising between parties, even if it is not called a court, and its jurisdiction is derived from statute or from the submission of parties, and it only has temporary authority to decide a matter ad hoc. It will accordingly not be necessary to canvass the authorities to which we were referred, and which deal either with issue estoppel or with the nature of judicial power. (citations omitted) 50 Given those comments, it is apparent that the question in the present case is, strictly speaking, left open. Daera Guba does not deal with issue estoppel, nor a tribunal subject to the unique dictates of federal judicial and administrative power. The context brings additional concerns, which are also intimated elsewhere: see eg Wiest v Director of Public Prosecutions (1988) 23 FCR 472, 522 and 526 per Gummow J; and there are alternative viewpoints: WJ & F Barnes Pty Ltd v Commissioner of Taxation (Cth) (1957) 96 CLR 294, 315 per Kitto J. There are good reasons, consistent with the statutory scheme established by the AAT Act, including ss 2A, 33, 42B and 43(6), to prefer a less rigid approach. Such an approach has found favour in the Tribunal: Matusko, 20-21 (although the principles to be applied may be further refined) and, tangentially, elsewhere: Rana v Military Rehabilitation and Compensation Commission (2011) 55 AAR 300; [2011] FCAFC 80, [26]-[28]; Minister for Immigration and Multicultural Affairs v Wang (2003) 215 CLR 518, 559 [134] per Kirby J. The policy of the doctrine of issue estoppel, that there must be an end to litigation, can be achieved by such an approach. Further, to the extent that policy is to prevent attempts to controvert earlier decisions about presently existing rights, a different model is more apt to disputes about the creation or destruction of rights (which the merely administrative decisions of the Tribunal must, constitutionally, effect: Re Cram; Ex parte Newcastle Wallsend Coal Co Pty Ltd (1987) 163 CLR 140, 149). 51 Although a "pervading tenet of the judicial system", the doctrine of issue estoppel is not apposite to the constitutional and statutory context of the Tribunal, and ought not to be extended to it. 52 Notwithstanding that conclusion, the present case can be disposed of by the particular features of the Seafarers Act, without the need to rely upon the precise scope of the statement of Gibbs J in Daera Guba. There is merit in that approach especially where this Court is without the assistance of real argument on the question of issue estoppel, and given its potential public importance.

The Tribunal's ability to reconsider issues previously determined 53 As identified above, the Tribunal applied the principles identified in Matusko, which it regarded as an exercise of the power in s 33 of the AAT Act, in determining whether it would consider the evidence which contradicted the causation assumptions underpinning its earlier decision. That decision had relied upon an earlier Tribunal decision in Re Quinn and Australian Postal Corporation (1992) 15 AAR 519, which had concluded that, whilst no issue estoppel would prevent a Tribunal from subsequently considering, in relation to a different decision, the same issue which has been the subject of an earlier decision, the power of the Tribunal to regulate its procedure under s 33 enabled it to refuse to consider evidence of such issues. Accepting that proposition, the Tribunal in Matusko concluded that a mechanism was required which would regulate the occasions on which issues which it had decided might be relitigated. At [33] it identified the following principles which it said should apply in such circumstances: (a) No formal issue estoppel arises from the Tribunal's findings in [the earlier decision], (b) The Tribunal should not generally allow relitigation of issues already decided, (c) But the Tribunal should use its flexible procedures to allow further consideration of issues where there is a reason to do so, for instance: (i) where there is a different decision, (ii) where there is a clear legislative intent, (iii) where the reconsideration decision is not final, (iv) where there has been a change in circumstances or fresh evidence, or (v) where justice to the parties requires a departure from the general rule. (d) The Tribunal should usually consider the evidence proposed to be called and make appropriate directions as to its admissibility during the hearing, as suggested in Re Quinn, rather than in a directions hearing prior to the substantive hearing. 54 In applying the above principles the Tribunal here determined there was no relevant change of circumstances or "fresh evidence" to overcome the general prohibition on reconsidering the issues underpinning the 2013 decision. The logical extension of this is, of course, that the Tribunal considers it is empowered to make a decision on review otherwise than in accordance with the evidence and material available to it. That is, it may make a decision that an employer is obliged to pay compensation when no such statutory obligation actually exists or that an employee is not entitled to compensation when, on the consideration of all relevant evidence, compensation should be payable. Moreover, it says that it is empowered to do so because the legislature has granted it power to regulate the procedure before it. With respect, the power of a tribunal to regulate the conduct of its proceedings ought to be used to facilitate decisions being made in accordance with legislative requirements rather than in contravention of them. 55 It must be kept steadily in mind that here, the consideration of the power of the Tribunal to refuse to consider the merits of a prior determination arises in circumstances where, under the Seafarers Act, the employer is expressly empowered to reconsider its prior decisions. Similar circumstances arise under the SRC Act. This is important as the conclusiveness of any administrative decision will be affected by the statutory scheme pursuant to which it is made: Godwin v Repatriation Commission (2008) 168 FCR 471, 482 [38]. It ought also be stressed that the consequences of the admixture of the provisions of the AAT Act and of any other legislation which does not afford the decision-maker the power of reconsideration are not dealt with in these reasons. 56 The Commonwealth's primary submission was that there is no general rule against re-litigation in the Tribunal or against reopening an issue decided by an earlier Tribunal decision, at least in so far as the decision being reviewed arises under the Seafarers Act. In support of that proposition it relied upon the combined effect of s 78 of that Act and s 43(1) of the AAT Act. It submitted that by s 43 the Tribunal exercised the power in s 78(2) and made the 2013 decision which was deemed to be that of the original decision-maker. In that respect it can be accepted that in substituting its decision for that of the original decision-maker, the Tribunal was doing so merely in an administrative capacity: Midland Metals Overseas Ltd v Comptroller-General of Customs (1991) 30 FCR 87, 97; Jolly v Commissioner of Taxation (Cth) (1935) 53 CLR 206, 214; and, in that capacity, its role was to do over again what the decision-maker did and to work out what it considered to be the correct decision. Subsequently, when Mr Snell sought compensation in relation to metastatic malignant melanoma, the Tribunal again stood in the stead of the Commonwealth as decision-maker and exercised all the powers which the Commonwealth was entitled to exercise in relation to Mr Snell's application for compensation. In particular, the Commonwealth said the Tribunal was vested with the power in s 78(1) to reconsider any prior decision made in relation to Mr Snell. So armed with those powers and discretions, its obligation was to assess whether he had sustained a relevant injury and, if so, the level of any subsequent impairment in accordance with the provisions of the Seafarers Act and, under s 43(1), affirm, vary or remit the decision. In that context, so the Commonwealth submitted, there was no room for an issue estoppel or principles akin to it which limited the material which might be considered. 57 The Commonwealth placed reliance upon Plumb v Comcare (1992) 39 FCR 236, 240-241. That case concerned the question of the power of the Tribunal, after the making of an initial decision in relation to a claimant, to consider subsequent decisions made by the employer in relation to the claimant's further claims relating to periods of time which were different to that which was the subject of the initial decision. The reasons in that case examined both the general nature of the Tribunal's powers to review decisions which come before it and s 62 of the SRC Act, which is the cognate provision to s 78. The point raised was not identical to that raised in the present matter as the decisions in question considered the applicant's claims for compensation in respect of two distinct periods of time. It was held that the earlier decision relating to the initial period of time was not a bar to, nor had any limiting effect on, the Tribunal's consideration of an application in relation to a subsequent period of time even though it related to the same injury. It was observed that the first decision was made on the evidence before the Tribunal at that time and, in making the initial decision, the Tribunal did not have power to decide the applicant's entitlements beyond the date of its decision. Lockhart J (with whom Black CJ and Gummow J agreed) at 240 concluded the Tribunal was not bound by its earlier decision and that was reinforced by the existence of s 62 which granted Comcare the power to reconsider its earlier decisions and the Tribunal in its stead could also reconsider them. His Honour said: This case is concerned with the 1971 Act and the 1988 Act. Those enactments define the powers of the determining authority, the decisions of which may be reviewed by the AAT. The determining authority's powers include the power of reconsideration conferred by s 62 of the 1988 Act upon the relevant determining authority, which in this case is the respondent, Comcare. Thus the combined operation of those provisions and s 43(6) of the AAT Act demonstrates that the decision of a determining authority may be reconsidered by it: see Hanna v Australian Postal Corporation (1990) 12 AAR 511. The AAT was not functus officio. 58 This provides substantial support for the proposition that, in reliance on s 78 of the Seafarers Act (or other cognate provisions), the Tribunal is entitled to reconsider earlier decisions of the determining authority and, it would appear, its own earlier decisions which are deemed to be of the determining authority. Although the cited passage was obiter, its weight cannot be doubted. It contains a recognition that the effect of the Tribunal exercising the power of a decision-maker which can reconsider its own decision is that the Tribunal is likewise entitled to reconsider those earlier decisions. In that respect, it is entitled to make subsequent decisions which are inconsistent with earlier ones. 59 The logical consequence of the Tribunal having the power to reconsider earlier decisions of the primary decision-maker is that it must also be able to reconsider its own earlier decisions which, likewise, are deemed to be of the primary decision-maker. 60 The focus of some of the debate during the course of the appeal concerned the decision of the Full Court in Hannaford. Although that decision arose under the cognate provisions of the SRC Act, the relevant legislative schemes and rights of review in the Tribunal are sufficiently comparable, in particular because under s 62 of the SRC Act the employer has the power to reconsider its earlier decisions. There, the employer, Telstra, had accepted liability to pay compensation to Mr Hannaford in relation to his claim that he had contracted the disease Ross River fever in the course of his employment. It duly paid him compensation for a period of time. Subsequently, it ascertained that he was not suffering from that disease at all, but from a different one which was not work-related. As a result it determined that it was not liable to pay any further compensation. It is apparent that it did not make any determination that it had not been obliged to make the payments which it had made. That said, the second decision was obviously inconsistent with the initial one and, necessarily, based on the assumption that it was in error. Telstra's decision was affirmed by the Tribunal however, on appeal, it was held that the Tribunal could not affirm the decision because the initial decision accepting liability was not before it and it could not go behind it. The primary judge's determination was reversed by the Full Court. Heerey J (Dowsett J agreeing) held at 255 [8] that the text, structure and underlying policy of the SRC Act did not suggest that any decision made under it "permanently enshrines" every finding of fact on which it is made. Central to this conclusion was that the Act specifically permitted the employer to reconsider its earlier decisions, at any time, and that included reconsidering any prior finding of fact. The contrary suggestion was seen as being inconsistent with the "modern, practical statutory scheme for the compensation of injured workers". His Honour also acknowledged at [10] that the SRC Act allows for "progressive and evolving decision-making allowing for the changes in circumstances which are inevitably likely to happen". Quite correctly he added: "This is in the interests as much of employees as employers." 61 Conti J (with whose reasons Heerey and Dowsett JJ agreed) considered the scheme of the SRC Act at length as well as several authorities relating to the ability of an employer, or the Tribunal on review, to reconsider issues of fact which it had determined in prior decisions. His Honour held at 273-274: 57 In my opinion, it should be concluded, upon the correct construction of the SRC Act, and in particular of the provisions thereof upon which I have focused attention in these reasons, that the AAT is empowered to make subsequent findings of fact in relation to the circumstances the subject of decision-making under ss 16 and 19 of the SRC Act, and also under ss 21 and 27 of the SRC Act, where the determination of the first instance decision-maker (here of course Telstra) made under the auspices of s 14 of the SRC Act remains in operation in the sense that it has not been the subject of any inconsistent outcome in the context of a subsequent review by the AAT. 62 In this respect, his Honour regarded the Tribunal as having power on review to reconsider the earlier determination of liability which was made under s 14 even though the decision on review only concerned the nature and extent of benefits to which the employee was entitled in the future and despite the fact the earlier decision remained in operation. The original decision did not crystallise the rights of the parties for all time. His Honour continued: The statutory scheme allows for progressive and evolving decision-making giving effect to the provisions of ongoing review of relief or entitlements in the nature of course of workers compensation, being review which allows for adjustment or change in the light of events and circumstances which may subsequently happen. The statutory scheme hence reflects a flexible scope for adjustment by way of decisions in the nature of awards to be made subsequently to the determination of s 14 liability, whether that determination be made in isolation, or in the context of decision-making concerning consequential relief that may be required in the light of evolving circumstances. It is therefore a scheme which allows progressively for ongoing relief, and is thus not comparable of course with the process of curial resolution of the traditional common law entitlement of an injured employee for damages as a consequence of the negligent conduct of an employer. The opening words of s 14(1) "[s]ubject to this Part…" are consistent with the flexibility inherent in the ensuing codification of the various facets of compensation envisaged. 63 A number of points arise from that passage. First, it would appear that an underlying assumption of his Honour's conclusion is the acceptance that, on review, the Tribunal was entitled to exercise all of the powers of the determining authority, including the power under s 62 of the SRC Act. Secondly, it is appropriate to emphasise that his Honour observed the sharp distinction between the process under the SRC Act and curial proceedings where the entitlements of the parties are finally determined. Thirdly, the words "subject to this part" in s 14 of the SRC Act were said to buttress the conclusion which was drawn from the structure of the compensation provisions themselves. The Tribunal's decision in the present matter sought to distinguish Hannaford on the basis the words "subject to this part" and "in accordance with this Act" did not relevantly appear. In the course of the reasons the Member said ([56]-[57]): [56] … Essentially, the [Seafarers Act] was designed to have a similar application as that of the SRC Act, and the Act contains parallel provisions to those in the SRC Act considered by the Full Court of the Federal Court in Hannaford. [57] However, while there is a similarity on its face, the Act is not identical to the SRC Act. Of some significance is the absence of the words "[s]ubject to this part", which Conti J emphasised in Hannaford, and the further absence of the words "in accordance with this Act" from s 26 of the Act. Without those qualifying words, it seems that liability under s 26 of the Act is of a subtly different nature to liability under s 14 of the SRC Act. This difference points away from there being clear legislative intent supporting re-litigation of issues in relation to that provision that have already been determined. Whether the differences in the liability arising under the two pieces of legislation are subtle or not need not be considered. Nevertheless, it is a misreading of Conti J's reasons to consider that his Honour emphasised the words "in accordance with this Act". As the passage from his Honour's reasons discloses, he identified the use of that expression as buttressing the conclusion he had reached from an examination of the structure and operation of the Act's provisions. Moreover, the Member overlooked the effect of s 24 of the Seafarers Act which specifically imposes liability to pay compensation "in accordance with this Act", including the provisions identified in paragraphs [24] and [30] above. That would include the operation of s 78. It must be recognised that, in reaching the conclusion he did, Conti J rejected any narrow interpretation of the analogous s 62 of the SRC Act. In the result, there is nothing which emerges from the different wording in the Seafarers Act on which the decision in Hannaford might be appropriately distinguished. 64 Another important decision is that of Cheung v Administrative Appeals Tribunal (2009) 176 FCR 20. It also considered the operation of the SRC Act. In that matter the Tribunal, in 2001, had determined that Australia Post was liable to pay Ms Cheung compensation for work related injuries and it did so. Ms Cheung made a number of subsequent claims to Australia Post for compensation for incapacity which were rejected. In exercise of its power under s 62, Australia Post also determined that it was no longer liable to make payments in respect of the initial claim. In 2008 the Tribunal affirmed Australia Post's determinations. Ms Cheung sought to hold the employer and Tribunal to the decision of 2001 in respect of Australia Post's liability to her. After considering the statutory regime Bennett J said in relation to the operation of s 62 (at 27 [43]): The reconsideration of a determination [under s 62] is not confined. There is no statutory requirement to apply the earlier determination or to take it into account. Inherent in the provision for reconsideration is the concept that that reconsideration is untrammelled by any previous determination. This does not preclude the determining authority from taking the previous determination into account but there is no requirement to do so. Similarly, there is no statutory requirement on the Tribunal to take into account any previous determinations or reconsideration decisions when reviewing a reviewable decision. 65 Subsequently, her Honour observed that, generally, there should not be relitigation without reason of the same issues before the same Tribunal where the relitigation involves the same facts and issues already determined (at 29 [49]). In such circumstances her Honour said that the previous determination would generally be regarded as establishing the matters actually decided and the grounds for the same and it is open to the Tribunal to proceed in that manner: Morales v Minister for Immigration and Multicultural Affairs (1998) 82 FCR 374 at 390. However, at [53] her Honour said: As Sackville J pointed out in Power 89 FCR at 525, s 43(1) of the AAT Act confers on the Tribunal the same powers and discretions as were available to the decision-maker, including the power provided in s 62(5) of the SRC Act to affirm, revoke or vary the delegate's decision that liability previously accepted had ceased. For the purpose of reviewing each reconsideration decision (ie each reviewable decision) the 2008 Tribunal could exercise all the powers and discretions conferred by the SRC Act on the reconsideration decision-maker (Power 89 FCR at 526). This included a power to consider whether Ms Cheung's conditions had ever been causally related to her work. This consideration involved the reconsideration decision-maker and then the 2008 Tribunal analysing all the necessary facts, including further medical reports, to determine whether or not there was a continuing liability. The 2008 Tribunal could have exercised its discretionary powers to exclude evidence recanvassing the issues resolved in the 2001 Tribunal decision (Power 89 FCR at 526 citing Re Quinn). No issue as to the Tribunal's discretionary power was raised in Power. 66 Bennett J went on to observe that the discretion to reopen an issue is not limited to the circumstances where an applicant's medical condition has changed. Her Honour observed there was no such limitation in the SRC Act and that the Act is silent on the use that might be made of prior determinations, reconsideration decisions and Tribunal decisions. It is a matter for the discretion of the determining authority to consider afresh the matter when the circumstances arose. Her Honour then observed (at 30 [56]): The Tribunal is not excluded from revisiting and making its own findings on questions of fact that have been the subject of findings by a prior Tribunal in an application to review a different reviewable decision. Until the subsequent decision is made, the earlier decision remains in operation. 67 The authorities to which reference has been made suggest that the existence of s 78 (or its equivalent) has two distinctive impacts on the decision-making process. First, the decision-maker may expressly reconsider an earlier decision and make a different decision in its stead. Secondly, a decision-maker faced with a further claim from an employee, may make a decision on the new claim which is inconsistent with the first decision in which case it can be said the original decision is implicitly reconsidered. However, the effect of this approach is that the original decision remains operative to the extent that it is not eclipsed by the latter. 68 The combined effect of s 43(1) of the AAT Act and s 78 is to allow the Tribunal, when reviewing a decision, to reconsider any earlier decision of the employer as well as any of its previous decisions which are deemed to be of the employer. That being so it would be inconsistent or lacking in coherency for the Tribunal to conclude that it was bound by an earlier determination. To do so would render the power of reconsideration inutile or, at least, substantially diminish its operative effect. 69 When a claimant seeks review of a decision to the Tribunal under s 88 of the Seafarers Act, the review is of a "reviewable decision", being a decision under s 78 which has reconsidered an initial decision. The employer's initial decision made in response to a claim by an employee is not reviewable by the Tribunal. A necessary first step before the Tribunal might undertake a review is that the initial decision is reviewed by the employer under s 78. It is the latter decision which is the "reviewable decision". When the Tribunal reviews that decision it exercises the power in s 78. Whether the decision under review was a reconsideration by the employer on its own initiative (s 78(1)) or on the request of the employee (s 78(2)) does not matter: the Tribunal stands in the stead of the employer and is invested with power to reconsider any prior decision which it had made in relation to the employee. This appears to be the consistent approach of the authorities. In Cheung, Australia Post had used its power under s 62 of the SRC Act to reconsider and reverse an earlier decision that it was liable to Ms Cheung under that Act. The Tribunal was reviewing that reconsideration. Bennett J observed that the Tribunal had all the powers of the determining authority under its power to reconsider, including s 62(5) of the SRC Act (being the cognate provision to s 78(6) of the Seafarers Act), such that it had full power to affirm, revoke or vary the initial decision. The Tribunal stood in the stead of the decision-maker which was entitled to reconsider its own previous decision such that it was equally empowered to reconsider those prior decisions and vary the decision under review as appropriate. Necessarily, that power in the original decision-maker to reconsider an earlier decision is antithetical to the notion that the decision-maker, or the Tribunal in its place, is somehow bound by or confined the making of that earlier decision. 70 When a decision-maker under the Seafarers Act or the Tribunal on review is reconsidering an earlier decision, the obligation is to make a decision as to the amount of compensation payable in accordance with the Act. The Act is concerned with conferring on injured employees benefits which employers are liable to pay in circumstances where the sustaining of an injury has the identified causal connection with the employee's employment. The entitlement to compensation and other benefits is not determined by a court but by administrative processes in which the Tribunal plays a role as an arbiter of factual matters relevant to the decision to be made. Central to the right of the employee to receive benefits is the satisfaction of the statutory criteria on which it is prescribed. Concomitantly, the liability of the employer under s 24 is to pay the amount determined "in accordance with this Act": see again the provisions identified in paragraphs [24] and [30] above. The Act imposes the circumstances when liability arises and the quantum of any compensation payable. Where it appears that an employee is entitled under the Act to receive benefits, there should be no restriction on that entitlement merely because of the existence of an earlier decision which erroneously denied the entitlement. If the employee is able to demonstrate to the employer that the earlier determination proceeded upon erroneous assumptions or incorrect evidence, s 78 enables the employer to reconsider that earlier decision and make a determination which properly reflects the established circumstances. If the employer fails to make the correct decision, the Tribunal may do so in its place. 71 In the ordinary course, absent some conferred statutory ability to re-exercise a power to determine a matter, once a power is exercised to determine the rights of a subject, the exercise is final and conclusive: Re 56 Denton Road, Twickenham [1953] Ch 51; Thrasyvoulou v Secretary of State for the Environment [1990] 2 AC 273, 289. Importantly, in respect of the power so exercised, the donee of the power is functus officio: Chandler v Alberta Association of Architects [1989] 2 SCR 848 at 861-862; Minister for Immigration and Multicultural Affairs v Bhardwaj (2002) 209 CLR 597, [52]. However, the schemes of the SRC Act and the Seafarers Act do not operate in that way. They are somewhat unique in that they provide for "progressive and evolving decision-making" in relation to claims for compensation. In the Seafarers Act, s 78 is an important integer of the scheme. It is an express conferral of a power to reconsider a previously made decision, granted in general discretionary terms and which is exercisable on the employer's own initiative. It is exercisable even though a seafarer has commenced (or concluded) review proceedings before the Tribunal in respect of the original decision and the employer is not limited as to the manner in which the earlier determination might be altered. Necessarily, this removes any suggestion that the power to determine a claim is exhausted once a decision is validly made. It may, on its own initiative or on request from the employee, reconsider any previous decision. 72 In the exercise of the power in s 78 there are no express statutory limits on the information which the decision-maker might consider in making any determination. As Bennett J observed in Cheung: "Inherent in the provision for reconsideration is the concept that that reconsideration is untrammelled by any previous determination." Any information in the possession of the decision-maker which is relevant to its satisfaction that the injury or disease was contributed to in a material degree by the claimant's employment or to the nature and extent of the injury or disease must necessarily be taken into account such that the liability of the employer to pay compensation in accordance with the Act can be determined. That is consistent with the obligation of the Tribunal to determine whether the decision under review is the correct or preferable one on the material before the Tribunal: Morales v Minister for Immigration and Multicultural Affairs (1998) 82 FCR 374. In general, this means the Tribunal is required to consider the relevant and probative material which the parties place before it or which it acquires for itself. It would only be in the most exceptional cases that it will exclude reliance on seemingly probative material: Re Tarrant and Australian Securities and Investments Commission (2013) 62 AAR 192, [77]. 73 In the present matter the decision which was the subject of review by the Tribunal was not a reconsideration of an earlier decision by the Commonwealth on its own initiative under s 78(1). It was a reconsideration of its earlier decision in relation to a new claim made by Mr Snell for what he said was the further sequelae of the "solar induced skin disease" which had been the subject of the 2013 decision. The Commonwealth submitted that it, as the original decision-maker, and the Tribunal on review, were able to reconsider the 2013 decision when considering the new claim. That decision, and in particular the conclusions concerning the cause of the skin damage, did not, so it was said, stand in the way of the determination of the new claim. Given what has been said above, that must necessarily be correct. That being so, there can be no limitation on the information which the decision-maker may consider in exercising powers under s 78(1) and, likewise, there can be no such limitation on the Tribunal. Where a party raises the existence of an earlier decision in the context of a consideration or reconsideration of a new claim, the power of the decision-maker to reconsider that earlier decision necessarily connotes the entitlement of the decision-maker to determine its correctness. That, in turn, necessarily means that the underpinning factual findings are open to reconsideration. 74 In the context of the above, the error of law which the Commonwealth submitted existed was that, given the wide powers of the Tribunal to consider the matter under review, it erroneously limited the evidence which it would evaluate in that process. In reliance on Matusko, the Tribunal accepted that s 33 of the AAT Act enabled it to control its procedures by refusing to allow a party to relitigate issues which had been determined by earlier proceedings save in particular circumstances. That included starting from a position that it ought not generally allow relitigation of issues already decided, and it would only do so where there was a reason. A number of examples were identified which were derived from the concept of issue estoppel and the concept of introducing "fresh evidence" on appeals. 75 In the circumstances of the present matter that approach was erroneous. Whatever be the scope of the power under s 33, it cannot extend, in the case of reviews of the exercise of power under s 78 of the Seafarers Act (or s 62 of the SRC Act), to justifying the non-consideration of material relevant to the performance by the Tribunal of its statutory function. Its obligations on review necessarily mirror those of the decision-maker under s 78 which expressly gives the power to reconsider previous decision. It would be most incongruous were the decision-maker, when exercising the powers under that section, to have the obligation to consider all relevant information, but the Tribunal might refuse to do so on the basis that its ability to reconsider earlier decisions was somehow limited. 76 Given that the existence of an earlier decision does not give rise to any limitation on the material which the Tribunal might consider on a review of a decision under the Seafarers Act, what then is the position when it is confronted with the existence of an earlier inconsistent decision? The general approach of Bennett J in Cheung ought to be adopted. Her Honour's reasoning gives full force and effect to the operation of s 62 of the SRC Act which expressly authorises the determining authority to reconsider decisions once made. In undertaking that reconsideration, both the decision-maker and the Tribunal are required to make a decision in accordance with the Act which necessitates assessing all material relevant to the issues to be decided. As Bennett J observed, the power in s 78 is untrammelled and there is no requirement to consider or take into account the earlier decision or to apply it. An earlier decision by the decision-maker (including an earlier decision of the Tribunal which is deemed to be that of the decision-maker) is information or material with which the Tribunal may inform itself (s 33(1)(c) of the AAT Act) and it can give it the weight which it considers to be appropriate. Where no new evidence has been advanced which relevantly undermines or alters the effect of the earlier decision it is most likely that, if the application for review is not disposed of in a summary manner, the earlier decision will have significant if not overwhelming weight. Where, on the other hand, new information is available which suggests the earlier decision was based on incorrect facts or limited knowledge, be it scientific knowledge or otherwise, the weight which might be afforded to the earlier decision may be minimal or non-existent. 77 The obligation of the decision-maker and of the Tribunal on review is to consider the material relevant to the claim being advanced. There is nothing in the scheme of the Seafarers Act which suggests that some higher justification for the reception of material is required. There is nothing which requires commencing the decision-making process with any predisposition that any relevant material ought not to be considered merely because the issue to which it is relevant has been determined as part of an earlier decision. To the contrary, the power to reconsider earlier decisions negates the suggestion that the entity exercising the power should or could refuse to take into account any relevant material. To do so would necessarily diminish the power to reconsider. Additionally, it may deny a claimant their entitlement under the compensation scheme or impose on an employer a liability for compensation for which it is not responsible. It would also impose a rigidity on the flexible and continuous decision-making process provided for in these compensation schemes. To the extent to which the decision in Matusko might suggest otherwise, such an approach is inconsistent with the statutory regimes in the Seafarers Act or the SRC Act. 78 That is not to say that dissatisfied employees under the Seafarers Act might simply make repetitious claims based on substantially the same facts and require the Tribunal to constantly review the rejection of the same by the employer. The Tribunal has considerable power under s 42B to expeditiously deal with any such applications for review. Such proceedings may be easily seen as frivolous, vexatious, misconceived or lacking in substance. Alternatively, they may be seen as an abuse of process and it is to be kept in mind that the categories of cases which fit that description are not closed and cannot be exhaustively defined. A careful review of the authorities concerning the concept of abuse of process was undertaken by Perry J in Novosel v Comcare (2017) 72 AAR 269 at [104]-[114]. Nevertheless, before the Tribunal determines to dismiss a proceeding relying on s 42B it would need to be satisfied that the proceeding was of such a nature that the issues raised should not be accorded a proper hearing. 79 Nor is it likely that an employer will inappropriately rely on s 78(1) to reconsider matters settled by the Tribunal without justification. That will inevitably lead to further proceedings in the Tribunal with the result that the original decision will be restored and the employer will be liable for the costs of such proceedings under s 92 of the Seafarers Act. 80 The conclusion to be drawn from the above is that the Tribunal erred in applying the principles in Matusko to the matter before it. Its obligation was to consider the material relevant to the decision which it was obliged to make. It was not limited in that consideration by the fact that some issues relating to the consequences of sun exposure to Mr Snell's conditions had been the subject of its prior decision. That decision created no limitation on the issues which it might decide nor as to the material which it might consider. The Tribunal erred by assuming that it ought start with a predisposition against receiving evidence relating to issues previously decided. The Commonwealth has established the Tribunal proceeded upon an error of law and the decision must be set aside. 81 For Mr Snell, it was submitted that, despite what was said by the Tribunal as to the principles which it intended to apply in determining whether to allow the issue of causation to be relitigated, there was no bias one way or the other in the actual decision. That is, it was said that the Tribunal did not actually start with the presumption that there should be no litigation of any issue which had previously been determined or that some reason had to be established before that could occur. That submission cannot be accepted. It is clear that the Tribunal sought to apply the principles in Matusko and commenced with a predisposition to the effect that the issue of the cause of Mr Snell's injury should not be relitigated. There are several passages in the reasons of the Tribunal where it indicated that this was the process which it was following. For example, paragraph 45 of the Tribunal's reasons and the heading which precedes it provide: Should the Respondent be prevented from re-litigating this issue? 45. As noted above, once it has been established that an issue in a matter is the same as one that has been previously decided, the presumption that matters should not be allowed to be re-litigated arises. This presumption is neither final nor definite. Rather, the Tribunal must then turn to determining whether its discretion to allow for re-litigation should be utilised. 82 That is a fairly clear indication that the Tribunal approached the matter with a predisposition against allowing reconsideration of the previous decision and the submission that the Tribunal did not act this way must be rejected. Moreover, it would be a practice fraught with difficulty for a court on review or on appeal to disbelieve that the Tribunal did not faithfully reason in the manner in which it expressly said that it did. 83 It was submitted by the Commonwealth that the case which it now seeks to advance was not inconsistent with the 2013 decision. It was said that decision was concerned with the skin conditions then being suffered, being removed melanomas and the like, and the case now being advanced concerned the metastatic malignant melanomas which, so it was said, were caused by childhood exposure to sun. The difficulty with that submission is that the Tribunal found that the metastatic malignant melanomas had been caused by, developed from or were part of the same condition as the solar induced skin disease which was the subject of the earlier decision. It was not suggested that this finding was vitiated by jurisdictional error. Necessarily, that finding, linked with the 2013 decision, had the consequence that the suggestion now being advanced by the Commonwealth would be inconsistent with the 2013 decision because the logical consequence of accepting the Commonwealth's argument would be that the solar induced skin disease was not contributed to in a material degree by Mr Snell's employment. The Commonwealth's submission in this respect cannot be accepted.

Even if the Matusko principles were correct, they were misapplied 84 As an alternative the Commonwealth also argued that, even if it were the case that the Matusko principles were appropriate to use in the exercise of its discretion, the Tribunal misapplied them. Although, given the above conclusions, it is not necessary to decide this question, as each party made submissions on it, it is appropriate to consider the veracity of the argument.

Did the Tribunal fail to recognise the existence of two separate injuries? 85 The Commonwealth submitted the Tribunal erred by failing to recognise the existence of two separate injuries because it found that the impairment for which Mr Snell most recently claimed, the metastatic malignant melanoma, arose as a consequence of the solar induced skin disease. It was said that, had the Tribunal correctly identified the existence of two separate injuries, it would have necessarily considered the new or fresh evidence which was being advanced as to the cause of the present impairment. In support of this the Commonwealth submitted that there was no evidence the malignant melanomas which were excised prior to 2013 could have metastasised so as to be the cause of the present condition. It referred to the finding at paragraph 22 of the reasons of the Tribunal which was: I find that the possibility of one of the litany of skin cancers and conditions from which the Applicant was suffering at the time of the 2013 decision transforming or metastasising into metastatic malignant melanoma was both squarely within the contemplation of the parties and of the Tribunal at the time of the 2013 decision. 86 This finding was made in the context of the Tribunal ascertaining what issues existed between the parties prior to the making of the 2013 decision. The Commonwealth submitted that finding was erroneous because it was not supported by any evidence but, nevertheless, it was used to support the finding at [27] that "the Applicant's present condition - metastatic malignant melanoma - had its genesis in one of the melanomas from which the Applicant has suffered." 87 These submissions should be rejected. There was before the Tribunal sufficient evidence for it to conclude that the metastatic malignant melanoma had arisen from or been caused by the malignant melanomas which were the subject of the 2013 decision. In the course of the hearing, Dr Wagner, being one of the experts engaged by Mr Snell, agreed that Mr Snell's present condition was attributable to an earlier malignant melanoma and probably one which had been excised. That reference to the ones which had been excised was a reference to those which were the subject of the 2013 decision. Further, for the purpose of his claim for solar induced skin disease in 2012, Mr Snell obtained a report from Dr James Muir, which identified that Mr Snell faced a risk of the existing melanomas metastasising. Dr Muir said: This level [of impairment] could change should he [the Applicant] develop metastatic disease from his previous malignant melanomas or develop more skin malignancies in the future. This report was before the Tribunal which made the decision under appeal. 88 The Tribunal noted that the evidence of Professor Fox, who had been called by the Commonwealth, also supported the possible existence of a link between Mr Snell's present condition and him previously suffering from malignant melanoma. The Tribunal concluded at [27]: Thus, the weight of medical evidence presently before me supports the contention that the Applicant's present condition - metastatic malignant melanoma - had its genesis in one of the melanomas from which the Applicant has suffered. It is of some benefit, at this stage, for me to consider whether it is the 2015 melanoma or a previous melanoma that spawned the Applicant's present condition. 89 It was not suggested by the Commonwealth that the evidence recited by the Tribunal in this respect was not an accurate reflection of the material which had been before it. That being so, there was substantial evidence supporting the Tribunal's conclusion in this respect and the submission by the Commonwealth that there was none cannot be sustained. 90 The Commonwealth next submitted that, even accepting the above nexus between the current disease and the solar induced skin disease which Mr Snell suffered in 2013, the conditions were separate injuries. That being so, as the submission went, the Tribunal refused to consider the reception of new evidence of causation in the report of Professor Fox on the erroneous ground that the injuries were the same. In support of the submission that the two conditions were different diseases for the purposes of the Seafarers Act, reliance was placed on the decision of the High Court in Canute v Comcare (2006) 226 CLR 535 [34]-[36] (Canute). It was submitted that this decision required the solar induced skin disease and the metastatic malignant melanoma to be treated as separate injuries and, as such, the Tribunal was required to permit relitigation of or, more accurately, to consider afresh the cause of the second injury. 91 The decision in Canute supports the conclusion that additional impairment of a separate and distinct kind from that which has initially been compensated arising from a single workplace event is to be treated as a different injury and assessed as such. However, that treatment is only relevant to the question of the assessment of the degree of impairment for which compensation is payable. The two different kinds of impairment constitute separate injuries and are individually compensable. That said there is nothing in the reasons of the High Court which suggests that the additional consequences of a workplace incident are to be treated as if they resulted from separate causes. Even if, when assessing the level of Mr Snell's impairment resulting from sun exposure during his employment, the solar induced skin disease and the metastatic malignant melanoma are to be treated as separate injuries and the degree of impairment arising from each is separately calculated, that does not require the Tribunal to proceed upon some fictional footing that the causes of the injuries are equally distinct. The concern of the High Court in Canute was the manner in which assessment of impairment occurred in relation to "consequential injuries". It said nothing about the evaluative process of ascertaining the factual causation of the injuries. 92 In addition, in the present case, the finding of fact made by the Tribunal was that the metastatic malignant melanoma was not a secondary impairment of a different kind consequent upon the sun exposure during employment. It was merely the appearance of an additional symptom arising from the single event and the initial disease. The Tribunal found that the more recent condition had its genesis in one of the melanomas which were the subject of the 2013 decision. That was the basis on which the Tribunal sought to distinguish Canute and there was evidence which supported that factual conclusion. 93 It follows that the Commonwealth's submission, that because distinct consequential impairments are to be treated as separate injuries for the purposes of assessing compensation, they must be treated as separate injuries in any factual analysis, should not be accepted.

Was there fresh evidence? 94 The Commonwealth next submitted that the Tribunal misunderstood the meaning of "fresh evidence" such that it then misapplied the Matusko principles. It specifically referred to the research undertaken by Dr Vuong and others which was reported in an article "Occupational sun exposure and risk of melanoma according to anatomical site" (International Journal of Cancer, 2014) and which had been referenced by Professor Fox in his report. It also relied upon the evidence of Mr Snell which was adduced in cross-examination at the hearing of the Tribunal to the effect that he had never sustained sunburn while going to sea and that it was only as a child that he suffered sunburn and blistering. That was significantly different to the evidence which had existed when the 2013 decision was made. At that time a report of Dr Muir indicated that Mr Snell had related a history of having been regularly sunburnt whilst at sea. Further, Mr Snell had provided a statutory declaration in 2011 for the purposes of his initial claim and, in that, he also asserted that he was regularly sunburnt whilst at sea. 95 The essence of the Commonwealth's complaint in this respect is that these pieces of evidence were mischaracterised by the Tribunal as not being within the concept of "fresh evidence" with the result that it misapplied the evaluative process required of the Matusko principles. It submitted that the evidence of the article by Dr Vuong and others had not been produced as at 2013 and Mr Snell's recanting of his earlier evidence about sustaining sunburn at sea could not reasonably have been acquired because it was not known that he would recant the assertions in his statement or in Dr Muir's report. 96 The Tribunal determined that there were in existence at the time of the 2013 decision four other reports which were to the same effect as Dr Vuong's. From that, it reasoned that the evidence in question, being that a view that the cause of metastatic malignant melanoma is solar skin damage which was sustained as a child, was neither new evidence nor was it fresh evidence. It also considered that the evidence of Mr Snell as to when he was sunburnt given under cross-examination was reasonably available to the Commonwealth at the time of the 2013 decision because, had it not agreed to the terms of the decision, it could have cross-examined Mr Snell at a hearing to the same effect. 97 In oral submissions Mr Hanks QC for the Commonwealth submitted that the Tribunal erred in finding the evidence was not "fresh evidence" because it misunderstood the effect of the decision in Hannaford. It was said that arose in two ways. First, because the Tribunal did not understand that a finding on liability under the SRC Act did not permanently enshrine every finding of fact on which an initial determination of liability was made. Secondly, because it distinguished the effect of that decision on the operation of the Seafarers Act by reference to the absence of the words "subject to this part" and "in accordance with this Act" in key sections of the latter Act. Just how those errors related to the Tribunal's conclusion with respect to the fresh evidence point was never explained. 98 In any event, the conclusion that the evidence now sought to be relied upon was reasonably available prior to the 2013 decision was a question of fact which the Tribunal was entitled to determine in the course of its hearing. Even if there was some error in reaching that conclusion, it was an error which the Tribunal was entitled to make. That conclusion is particularly apt in the circumstances where, by s 33(1)(c) of the AAT Act, the Tribunal is not bound by the rules of evidence and is entitled to inform itself as it thinks appropriate.

Conclusion 99 The Commonwealth has succeeded on its primary ground to the effect that the Tribunal erred in applying inappropriately restrictive principles to the manner in which it would receive evidence. In that respect the Tribunal made an error of law and the matter must be remitted to it. 100 The parties will be heard as to costs. I certify that the preceding one hundred (100) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Chief Justice Allsop and Justices Reeves and Derrington.