Minister for Home Affairs v DMA18

The High Court of Australia considered appeals by the Minister for Home Affairs concerning the application of section 494AB of the *Migration Act 1958* (Cth). The dispute arose from proceedings instituted in the Federal Court by individuals detained in a regional processing country, alleging the Commonwealth breached a duty of care to provide adequate medical treatment on Nauru. The Minister contended that section 494AB(1) barred these proceedings.

The central legal issue before the High Court was whether section 494AB(1) of the *Migration Act* limited the jurisdiction of the Federal Court or barred the remedy sought by the respondents. Specifically, the Court had to determine if the respondents' proceedings, which alleged a breach of duty of care regarding medical treatment, engaged the operation of section 494AB(1)(a), (ca), or (d) of the Act. The Court also considered the effect of section 494AB(3), which preserved the jurisdiction of the High Court under section 75(v) of the Constitution.

The High Court reasoned that section 494AB(1) operates as a defence that the Commonwealth may plead, rather than an absolute jurisdictional bar. It applies only to proceedings against the Commonwealth where one of the issues raised in those proceedings relates to the specific subject matters enumerated in section 494AB(1). The Court clarified that the provision is not limited to judicial review proceedings but is also not so broad as to encompass all claims remotely connected to regional processing. The determination of whether the identified subject matters are at issue depends on the pleadings and the relief sought. The Court noted that the legislative history of Australia's regional processing regime informed this interpretation, indicating a legislative intent to limit proceedings related to this regime in specific ways.

The High Court allowed the appeals, setting aside the orders of the Full Court of the Federal Court. The Court determined that section 494AB did not prevent the institution of the proceedings. It further held that while the proceedings could not be continued as currently framed if section 494AB applied, the Commonwealth could plead section 494AB as a defence. The respondents, if advised, could seek to plead this defence and apply for a stay of proceedings, with any decision on amendment of pleadings or granting a stay being a matter for the Federal Court to determine.