38 See also ASP v Commonwealth [2016] FCAFC 145; (2016) 248 FCR 372 at [21]–[23].
39 In BMF16 at [25]–[26], Bromberg J succinctly describes the assessment as follows (the passage was recited by the primary judge at [51]):
Whilst a legislative scheme may not specify a time limit, it may nevertheless throw light on what was intended as a reasonable time for the performance of the statutory duty in question. The subject matter of the power, its statutory purpose, the importance of its exercise both to the public and to the interests of the persons it is directed to address, the nature of those interests and the likely prejudicial impact upon interest-holders of any delay, as well as the practical limitations which attend the particular exercise of the power by reason of the nature of the decision required and the preparation, investigation and considerations called for, are all likely to be relevant to what, in the context of the particular legislative scheme, was intended as a reasonable time for the performance of the duty.
To my mind, the question that s 7(1) poses is really this: by reference to the statutory scheme in which the decision-making power is found, has there, in all of the circumstances, been an unreasonable delay in the making of that decision…
40 The "usually high threshold for a conclusion that a power has been unreasonably exercised as a matter of law", was recently reiterated by the High Court in Ismail v Minister for Immigration, Citizenship and Multicultural Affairs [2024] HCA 2; (2024) 98 ALJR 196 at [25]. See also Minister for Home Affairs v DUA16 [2020] HCA 46; (2020) 271 CLR 550 (DUA16) at [26] citing Minister for Immigration and Border Protection v SZVFW [2018] HCA 30; (2018) 264 CLR 541 (SZVFW) at [11], [52], [89] and [135].
41 In this regard the primary judge at [52] quoted DUA16 at [26]:
A requirement of legal reasonableness in the exercise of a decision-maker's power is derived by implication from the statute, including an implication of the required threshold of unreasonableness, which is usually high. Any legal unreasonableness is to be judged at the time the power is exercised or should have been exercised. It is not to be assessed through the lens of procedural fairness to the applicant. Instead, whether the implied requirements of legal reasonableness have been satisfied requires a close focus upon the particular circumstances of exercise of the statutory power: the conclusion is drawn "from the facts and from the matters falling for consideration in the exercise of the statutory power".
42 The appellant pointed to no authority to support the proposition that the consideration of whether a delay is unreasonable starts with an assumption that an agency is adequately resourced, such that the lack of resourcing is a consideration (except in limited circumstances) that is not relevant thereafter. Nor did he point to any authority which suggests that any explanation for a delay that refers to resourcing is not a relevant consideration (or is of limited relevance) in assessing whether it has been established that the delay is unreasonable.
