First reason
59 I will deal first with Bignold J's approach.
60 I will assume for the immediate purpose that the phrases "not inconsistent with" and "substantially the same development" have the same meaning, imputing the same nature and degree of allowable variance relative to the development consent.
61 I will also assume, for the immediate purpose, that there is no material difference between the variations in the case of the modified development (relative to the development consent) and the variations in the case of the construction certificate (relative to the development consent). (There is the concession that the variations in the case of the approved development exceeded those in the case of the construction certificate, which is not a material difference for immediate purposes.)
62 There is nonetheless a significant difference between the two provisions. Section 96 calls for the opinion of a tribunal (the consent authority or the court on appeal) as to whether, in nature and degree, the variation is allowable. By contrast, cl 145 calls for a finding of fact by a tribunal (the court) as to whether another person (the certifying authority; in this case, the applicant) was satisfied that the variation, in nature and degree, was allowable. In one case it is a tribunal's own opinion that counts. In the other, it is a tribunal's finding of fact as to the opinion of the certifier that counts.
63 There is a fundamental difference in this respect between the question arising under s96 and the question arising under cl 145. It is a difference which exists independently of any difference in the nature, degree or content of the variations which present for consideration under the respective provisions. For this reason alone, the questions are not the same.
64 Bignold J did not put the point quite that way, but, in substance, it is what he said at [58 - 60] of the judgment.
Second reason
65 A second reason for the question being different arises from yet a further difference between the two provisions.
66 Section 96 involves a comparison between a proposed development and the development consent. Clause 145 involves a comparison between a construction certificate and the development consent. The questions arising under the respective provisions are different in that respect.
67 The applicant invokes the concession that, on the facts of this case, the variations approved pursuant to s96 were more extensive than the variations in the construction certificate relative to the development consent. That, the applicant says, is not a material difference but, on the contrary, demonstrates that an adverse finding in the prosecution, grounded as it is on cl 145, would be inconsistent with the prior approval of a modified development by Commissioner Murrell pursuant to s96.
68 This is recourse to the facts of the case to show that, as a matter of reasoning, there is no inconsistency between questions which, on their face, are different. Such recourse to the facts is impermissible under the principles relating to estoppel by res judicata and issue estoppel. By parity of reasoning it is impermissible under the principles applicable to the extended doctrine of res judicata.
69 In this regard, I need only cite the decision of the High Court in O'Donel v The Commissioner for Road Transport & Tramways (NSW) (1938) 59 CLR 744. The appellant, O'Donel, brought two proceedings for compensation for incapacity due to blindness allegedly resulting from injury received on 19 March 1933 in the course of his employment with the respondent. In proceedings in the Supreme Court of NSW, pursuant to s124 of the Transport Act 1930, the appellant recovered the salary he was receiving at the time of the injury for the period from 14 September 1934 to 15 February 1935. In the second proceeding, brought in the Workers Compensation Commission of NSW, the appellant claimed workers' compensation from 15 February 1935 for incapacity due to blindness resulting from the same injury. The Commission dismissed the claim, being satisfied that the appellant's blindness resulted from a progressive, chronic disease from which the appellant was suffering before 19 March 1933 and thereafter, rather than from the injury received on 19 March 1933. The Commission held, accordingly, that the injury received on 19 March 1933 did not cause any incapacity for work after 15 February 1935 and dismissed the claim.
70 On appeal from the decision of the Commission, it was argued that the Commission was constrained by the doctrine of res judicata to disallow evidence adduced by the respondent that the appellant's blindness in the period after 15 February 1935 resulted from disease rather than from injury received on 19 March 1933.
71 It was held by the High Court that there was no estoppel. The earlier proceedings had determined only that the appellant's blindness up to 15 February 1935 was caused by the injury received on 19 March 1933. Was it not then the same blindness which continued thereafter? Latham CJ said, at 758:
When the matter came at a later date before the Workers' Compensation Commission the continued existence of total blindness was proved. It is an easy inference to conclude that the blindness existing at the later date had the same cause as the blindness which existed at the earlier date. It is, as it appears to me, at this point that the real difficulty of the case appears. How far can an estoppel be extended by inference?
72 His Honour held it could not. He said, at 758-9:
Now it cannot possibly be said that the Supreme Court, by a judgment relating only to a period which ended on 15th February, thereby made any direct or actual decision or determination as to any matter or state of affairs whatever which existed at a later date. That judgment did create an estoppel as to one proposition - but that estoppel cannot operate to establish by estoppel another proposition which follows from the former proposition only when that proposition is combined with others the establishment of which depends upon evidence or assumption.
73 That the plaintiff's blindness before and after 15 February 1935 had the same cause depended on evidence. His Honour concluded, at 759:
The question which it decided is, as the Full Court of the Supreme Court said, not eadem quaestio. In my opinion the plaintiff's contention therefore fails.
74 Evatt and McTiernan JJ were of the same opinion for substantially the same reasons.
75 The doctrine of extended res judicata is designed to bring the principles of estoppel by res judicata and issue estoppel into operation notwithstanding that there is a difference in the parties. The reasoning in O'Donel applies. It follows that the patent difference between the questions arising under the two provisions cannot be cured by recourse to the factual relationship between the matter decided by Commissioner Murrell and the matter to be decided in the prosecution.
Third reason
76 A third reason for the questions not being the same relates to the function of the respective provisions and the construction to be given to them having regard to that function.
77 The applicant submits that the phrases "substantially the same development" and "not inconsistent with" have the same ordinary meanings. That may be so in ordinary usage. However, the fact that the regulation-making authority has chosen different language in cl 145 from that used by the Parliament in s96, where the two provisions are part of the same code, strongly suggests that a distinction was intended. More particularly, both terminologies call for a judgment which cannot be made in vacuo and which necessarily takes into account the function of the respective provisions.
78 From this perspective, the formulae "substantially the same development" in s96 and "not inconsistent with" in cl 145 cannot be seen as having the same import. Put another way, it is entirely possible that the same variation (or a more extensive variation, as in this case) might be seen as resulting in "substantially the same development" within the meaning of s96, and yet as being incapable of accommodating the requirement that the certified development be "not inconsistent with" the development consent within the meaning of cl 145.
79 That is because s96 and cl 145 have different functions in the scheme of the legislation. The function of cl 145 is to ensure that the development as built will be in accordance with the development consent. The function of s96 is to allow modification of the development consent (albeit with a threshold limitation). In this context, the kind of variation contemplated by s96 and by cl 145 may be quite different in character. Variations which infringe the limitations on development expressly or impliedly imposed by the development consent may be seen as "inconsistent with" the development consent within the meaning of cl 145. On the other hand, s96 may be seen as contemplating relief from strict compliance with such limitations under the formula "substantially the same development".
80 There is also, the degree of variation which the respective provisions will accommodate. Clause 145 is proscriptive. It prohibits the issue of a construction certificate unless the certifier is satisfied of the matter specified. Section 96, on the other hand, is a facultative, beneficial provision. As such it is to be construed and applied in a way that is favourable to those who are to benefit from the provision: Re Kearney; Ex parte Jurlama (1984) 52 ALR 24, 28; Zangzinchai v Millanta (1994) 125 ALR 265, 272.
81 It is unnecessary to decide whether cl 145 is to be applied strictly although that argument is available. It is sufficient that s96 is to be construed liberally on grounds which do not apply to cl 145. It follows that s96 may accommodate a greater degree of variation in the proposed development referrable to the development consent than cl 145 will accommodate.
82 For that reason also, the finding that the approved development was "substantially the same development" within the meaning of s96 does not necessarily imply that the plans the subject of the construction certificate were "not inconsistent with" the development consent within the meaning of cl 145. And that is so notwithstanding that the approved development involved more extensive variations than were involved in the construction certificate.
83 Because of disparity in the nature and in the degree of variation which may be accommodated by the respective provisions, the questions arising under the two provisions are not necessarily the same.