5. The correspondence sent to the Applicant with the first review decision, also dated 16 May 2025, informed the Applicant of his right to lodge an application to apply for second review in the Tribunal, and of the 28-day time limit[2] that applied.
6. Rebuttable statutory presumptions dictate when service of the first review decision will be taken to have been effected on the Applicant.[3] As a result of the application of those presumptions, and where no evidence to the contrary has been provided, it is presumed that he was served with a copy of the first review decision no later than 3 June 2025.
7. The Applicant had 28 days from being provided with the objection decision in which to lodge an application for second review with this Tribunal. He lodged the application for review about two weeks late, on 15 July 2025. He sought to be allowed to proceed with the application for second review, notwithstanding that it was lodged out of time.

1. I heard the application for an extension of time on 25 February 2026. The Applicant and the Other Party gave evidence and made submissions. The Other Party opposed the grant of an extension of time. The Respondent appeared through Mr Taverniti, solicitor, and also opposed an extension of time.
2. For the following reasons, I will refuse to extend time for the Applicant to lodge his application for second review.

1. The Child Support (Assessment) Act 1989 (Cth) (the 'Act') provides for Child Support to make an administrative assessment of child support. Child Support must make the assessment using a formula containing variables such as the parents' adjusted taxable incomes and the respective percentages of care they have provided, or are likely to provide, for each relevant child, in the 'care period' that Child Support decides it is appropriate to consider.
2. Once an assessment of the percentage of care is made and applied in the formula, Child Support continues using that percentage of care until it is informed, or becomes aware, that an anticipated pattern of care did not eventuate, or that it did eventuate but subsequently changed.
3. If notified of an alleged change in the pattern of care of a child, Child Support must consider whether such a change occurred. If Child Support is satisfied that it did, then the percentages of care used in the assessment may, or in some cases must, be revoked[4] and another assessment made using newly determined percentages of the actual care the parents provided or are likely to provide to the child.
4. However, in some circumstances, Child Support may also apply another care percentage determination for an interim period ('interim care determination') under ss 51 and 53 of the Act. Prior to the decision of CMU23, referred to by the Tribunal on first review, the prevailing view was that an interim care determination could be made irrespective of whether the existing percentages of care had been revoked under ss 54F, 54G, or 54H of the Act.
5. However, as the Tribunal on first review explained, the decision of the Court in CMU23 made it plain that, at that time, the legislation only provided for an interim care determination to be made where the existing percentages of care were revoked under s 54G of the Act.
6. Whilst the Parliament subsequently amended the legislation, such that interim care determinations could also be made where the existing care determinations were revoked under ss 54F or 54H of the Act, it was explicit in respect of when that amendment was to have effect. Item 11 of sch 1 to the Social Services Legislation Amendment (Child Support and Family Assistance Technical Amendments) Act 2024 (Cth) ('Amendment Act') provided in that respect:

Application of amendments - child support > > The amendments of the Child Support Act made by this Schedule apply in relation to a determination that is to be or has been made under section 49 or 50 of that Act on or after the commencement of this item if the change of care day for the responsible person, and the child, concerned occurs on or after that commencement. (emphasis added)

7. The Amendment Act commenced on 29 March 2024.
8. The first review decision is, subject to an extension of time, amenable to second review by the Tribunal under s 131D of the Administrative Review Tribunal Act 2024 (Cth) ('Art Act').
9. I have power to extend the time for the Applicant to lodge his application for second review under s 19(2) of the Art Act if it is 'reasonable in all the circumstances to do so.' The overarching principle to be applied where an extension of time is sought, and the relevant legislation provides no explicit mandatory considerations that direct the exercise of the discretion, is that the Tribunal should consider any pertinent factors to determine 'what the justice of the case requires.'[5]
10. However, the starting position where the law provides a fixed period to make an application, subject to extension, is that proceedings commenced outside the statutory time limit will not be entertained.[6]
11. In considering the extension application, the Tribunal is only required to conduct a preliminary assessment of the apparent merit of the review if it proceeds, not to fully hear and determine it. However, the stronger the apparent merits the more likely that an extension of time would be appropriate.[7] On the contrary, '...an applicant should show that he or she has an arguable case. No doubt if the objection on the face of it is one which is frivolous or bound to fail as a matter of law it would be a futility to permit an extension of time to enable it to be considered.'[8] I am satisfied those principles, applied by the courts, are apposite in respect of applications of this nature.
12. When considering extensions of time in respect of applications of this nature, the Tribunal has commonly drawn on a line of authority that includes Hunter Valley Developments Pty Ltd v Cohen[9] ('Hunter Valley') and Englezos v Secretary, Department of Social Services.[10] Those decisions provide guidance by the Court on extensions of time to appeal from the former Administrative Appeals Tribunal ('AAT') to the Court.
13. Some care must be taken when transposing such guidance to a different context, to ensure that it is not considered to fetter the exercise of the discretion, or to raise permissible considerations to the status of being mandatory. However, I am satisfied that the considerations set out in those decisions are all permissible, and commonly relevant considerations in respect of applications of this nature. They provide a helpful framework to consider such applications and include:

(a) Whether the substantive application has reasonable prospects of success;[11] > > (b) The length of the delay;[12] > > (c) The explanation for the delay;[13] > > (d) Any prejudice to the parties or persons affected by the decision;[14] and > > (e) The public interest.[15]

14. Further, I agree with comments made by Senior Member O'Donovan of the former AAT in NLLQ and Child Support Registrar[16] at [4], that:

In this particular statutory context, the reasons for delay and the effect on the orderly payment of child support should be scrutinised very closely. It should also be noted that a statutory context where multiple opportunities are given to address the merits of a decision is very distant from a first instance application to a court on a question of the lawfulness of conduct.

1. I accept that the Applicant was seeking legal advice and was under the care of a psychologist when he delayed in lodging his application for second review. He was also seeking to reinstate his time with the child. His delay, of approximately two weeks, was not extensive. However, whilst those issues give context to his delay, they do not provide a compelling explanation for it where the Applicant was advised of the relevant time limit that applied. I also accept there is obvious prejudice to the Applicant if an extension of time is not granted, as the application for review will not proceed and he will be precluded from the possibility of a more favourable outcome.
2. There is no material prejudice alleged by the Respondent if the extension is granted, but I also need to consider the Other Party's position. As the courts have noted, albeit in the context of judicial proceedings where the level of prejudice may be higher, there is always a level of prejudice to a party to contested proceedings where expectations change, and finality is not achieved.[17] There may also be a debt caused by overpayment if the review proceeds and the Applicant succeeds in lowering his assessment by obtaining an interim care determination, in circumstances where the Other Party had ordered her life around, and utilised, the child support she has received based on the assessment as it applied at the time, and after the time for lodgment of the second review application had passed. This weighs against an extension of time.
3. The public interest generally weighs against an extension of time, noting that the 28-day time limit that applied to the Applicant is prescribed by legislation and indicates Parliament's intention that there ought to be finality in government decisions.[18] This is tempered, though, by the public's expectation that administrative decisions should be correct, and that a process exists for review, if necessary after an extension of time is granted.
4. In merits review, the prospects of success of an application are sometimes harder to assess than, for example, in an appeal or judicial review proceedings where specific error must be identified. If an extension of time is granted, all issues in relation to the application may need to be revisited and reconsidered if they are put in issue.
5. However, the Applicant does not challenge the Tribunal's finding on first review that it was bound to revoke the existing percentages of care and make the new assessments it did. Nor does he challenge the factual findings of the Tribunal on first review that meant the existing percentages of care needed to be revoked under s 54F of the Act.
6. In brief, s 54G of the Act was inapplicable, at least because there is no dispute that the Other Party was not 'making the child available' to the Applicant after the pattern of care for the child changed in October 2023, which was a prerequisite to the application of s 54G.[19]
7. What the Applicant says is that, as the interim care provisions in force in October 2023 were 'protective' in nature and existed to assist parents who are deprived of the level of care they are entitled to under orders of a court, Parliament ought to be understood to have been acting protectively of that position by enacting the remedial provisions that changed how the Act operates and allows interim care determinations where the existing determinations are revoked under ss 54F or 54G. So much may be accepted, but it is also clear that the Parliament made a deliberate choice as to how such remedial provisions were to operate when it enacted the Amendment Act, particularly item 11 to sch 1. The amendment cannot be interpreted as applying to the Applicant.
8. The outcome reached by the Tribunal on first review in respect of the availability of an interim care determination was mandated, on its unchallenged factual findings, by the decision in CMU23. The Tribunal is not entitled to look behind that decision, or to form a different view. Similarly, the Applicant made no legally coherent challenge to the Tribunal's finding that the subsequent amendment to the Act did not apply retrospectively to him. I am satisfied that the Tribunal was correct in that regard.[20]
9. The Respondent submits that, in those circumstances, the application has no apparent merit if an extension of time is granted and this should weigh determinatively against the extension of time.
10. I agree.
11. Weighing the considerations I have identified together,[21] I have decided to refuse to extend the time for the making of an application for second review.

1. Whilst I was reserved in this matter, the Applicant sought, by correspondence to the Registry, a stay of the decision under review. The Tribunal sought the views of the other parties. At the date of releasing this decision, only the Other Party had responded. She opposed a stay.
2. In any event, by s 32(2) of the ART Act, the Tribunal may stay the operation or implementation of the decision under review if it 'considers that it is desirable to do so for the purpose of ensuring the effectiveness of the review' (emphasis added).
3. Having determined that an extension of time should not be granted, no review will proceed. There is therefore no proper basis on which to grant a stay.

1. The application for a stay is refused.
2. The Tribunal refuses to extend the time for making an application for second review.

I certify that the preceding 39 (thirty-nine) paragraphs are a true copy of the reasons for the decision herein of Senior Member Suthers

..........[SGD]..............................................................

[1] The entity administered by the Respondent.

[2] Administrative Review Tribunal Act 2024 (Cth), ss 18(1), 131J; Administrative Review Tribunal Rules 2024, r 5(3).

[3] Acts Interpretation Act 1901 (Cth), s 29(1); Child Support (Registration and Collection) Regulations 2018 (Cth), reg 31; Evidence Act 1995 (Cth), ss 160, 163; Electronic Transactions Act 1999 (Cth), s 14A(1)(a).

[5] Brown v Federal Commissioner of Taxation [1999] FCA 563 ('Brown'), [59].

[6] Lucic v Nolan [1982] FCA 217.

[10] [2023] FCA 31.

[12] Ralkon v Aboriginal Development Commission [1982] FCA 153; (1982) 43 ALR 535, 550.

[13] Hunter Valley, [18]; Doyle v Chief of Staff [1982] FCA 124; (1982) 42 ALR 283, 287.

[15] Brisbane South Regional Health Authority v Taylor (1996) 186 CLR 541.

[16] [2023] AATA 867.

[17] See for example Ketteman v Hansel Properties Ltd (1987) 1 AC 189, 220 (Lord Griffiths).

[18] Re Commonwealth of Australia; Ex Parte Marks [2000] HCA 67, [16] (McHugh J).

[20] Social Services Legislation Amendment (Child Support and Family Assistance Technical Amendments) Act 2024 (Cth), sch 1, item 11.

[21] Zizza v Federal Commissioner of Taxation (1999) 55 ALD 451.