Consideration and determination
5 For the following reasons, we consider that the appropriate costs orders are as follows:
(a) in the proceeding in the Court's original jurisdiction (NSD1378/2020), the respondents should pay 80% of AOU21's costs, as agreed or taxed; and
(b) in the appeal proceeding (NSD1355/2020), there should be no order as to costs.
6 Unsurprisingly, the parties did not dispute the relevant principles concerning costs. Rather, their disagreement related to the application of those principles to the particular circumstances.
7 Under s 43 of the Federal Court of Australia Act 1976 (Cth), the Court has a broad discretionary power to award costs, which discretion must be exercised judicially, consistently with the purpose of the power and with regard to all relevant facts and circumstances (see, for example, Kazar (Liquidator) v Kargarian; In the matter of Frontier Architects Pty Ltd (in liq) [2011] FCAFC 136; 197 FCR 13 at [4] per Greenwood and Rares JJ).
8 In an appropriate case, the Court may award costs by way of apportionment, having regard to the parties' relative success or failure (see, for example, New South Wales Lotteries Corporation Pty Ltd v Kuzmanovski (No 2) [2011] FCAFC 152 at [12]-[15] per Siopis, Cowdroy and Tracey JJ).
9 It is appropriate to address the question of costs in relation to the original jurisdiction proceeding and the appeal proceeding together. This reflects what was said in our reasons for judgment at [4] that both proceedings raised substantively the same underlying issues. The appeal proceeding was dismissed primarily because the same points arose in the original jurisdiction proceeding (see at [8] and [224]). As was noted at [8], most of the hearing time was devoted to the original jurisdiction proceeding and oral argument on the appeal was heard only "briefly" thereafter.
10 We accept AOU21's submission that, while the outcomes of the two proceedings were mixed, he substantially succeeded. This is because, in the original jurisdiction proceeding, he successfully contended that the three preconditions in s 198AH(1A) of the Migration Act 1958 (Cth) were met and that the duty to remove him to a regional processing country as soon as reasonably practicable under s 198AD(2) was engaged. This was his principal contention. AOU21's success is reflected in the terms of the declaration made by the Full Court.
11 Nevertheless, AOU21 failed to establish any of his other claims for substantive relief (in particular his request for an order that he be released from detention, an order by way of mandamus to remove him to a regional processing country, an order in the nature of prohibition preventing his detention under s 189 of the Migration Act and a declaration that his immigration detention was unlawful). AOU21 also failed to establish that his detention was unlawful at any relevant time. His failure on these matters should be taken into account and reduce the costs order in his favour in the amount of 20%.
12 Turning now to the appeal, applying the normal rule that costs follow the event, the respondents would be entitled to their costs. The appeal was dismissed after the Court refused leave to permit the appellant to amend his notice of appeal so as to raise points which were not run at the trial in the (then) Federal Circuit Court. Significantly, however, as noted at [8] of our reasons for judgment, the respondents' opposition to AOU21 having leave to amend his grounds of appeal was based on an acknowledgment that the same points were made in substance in the original jurisdiction proceeding, with the consequence that it was not in the interests of the administration of justice to allow new points to be raised on the appeal when the same matters were ventilated in the original jurisdiction proceeding. This was the basis upon which we dismissed the appeal (see at [224]).
13 In substance, however, because of AOU21's substantial success in the original jurisdiction proceeding, the appeal was rendered redundant. The fact that it was formally dismissed does not truly reflect the relevant circumstances, including the interrelationship between the appeal and the original jurisdiction proceeding. In these unusual circumstances, we consider it appropriate that there be no order as to the costs of the appeal.
14 For completeness, it should be noted that on 4 March 2021, Griffiths J ordered that AOU21 pay the respondent's costs thrown away as a result of the amendments to his notice of appeal. That costs order should not be disturbed.
15 Orders will be made accordingly.
I certify that the preceding fifteen (15) numbered paragraphs are a true copy of the Reasons for Judgment of the Honourable Justices Griffiths, Mortimer and Perry.