Minister for Immigration and Border Protection v Makasa

The High Court of Australia considered an appeal by the Minister for Immigration and Border Protection against a decision of the Full Federal Court. The dispute concerned the Minister's power to re-exercise a visa cancellation decision under section 501(2) of the *Migration Act 1958* (Cth) after the Administrative Appeals Tribunal (AAT) had previously set aside a delegate's cancellation decision and substituted a decision not to cancel the visa.

The central legal issue before the High Court was whether the Minister could validly re-exercise the discretion to cancel Mr Makasa's visa on the same factual basis, notwithstanding the AAT's prior decision that the visa should not be cancelled. This involved an examination of the interplay between the Minister's powers under section 501(2) and the AAT's merits review function under the *Administrative Appeals Tribunal Act 1975* (Cth).

The High Court reasoned that the AAT's decision to set aside the delegate's cancellation and substitute a decision not to cancel the visa was a final determination of the merits of the cancellation at that time. The Court held that the Minister's subsequent attempt to re-exercise the power under section 501(2) on essentially the same factual basis, without any new or different circumstances arising, was an impermissible attempt to revisit a concluded administrative decision. The Court emphasised the principle of finality in administrative decision-making and the nature of merits review, which ordinarily concludes the matter unless new grounds arise.

The High Court dismissed the Minister's appeal, upholding the Full Federal Court's decision. This outcome affirmed that once the AAT has exercised its merits review function to substitute a decision not to cancel a visa, the Minister cannot simply re-exercise the original cancellation power on the same factual foundation.