s 189 — Detention of unlawful non-citizens — Migration Act 1958
Text of provision
189 Detention of unlawful non-citizens
(1) If an officer knows or reasonably suspects that a person in the migration zone (other than an excised offshore place) is an unlawful non-citizen, the officer must detain the person.
(2) If an officer reasonably suspects that a person in Australia but outside the migration zone is an unlawful non-citizen, the officer may detain the person.
(3) An officer must detain a person if:
(a) the person is in a proclaimed port; and
(b) the officer knows or reasonably suspects that the person is a non-citizen; and
(c) the person has not been immigration cleared.
(4) An officer must detain a person if:
(a) the person is at an airport; and
(b) the officer knows or reasonably suspects that the person is a non-citizen; and
(c) the person has not been immigration cleared.
Plain English
Section 189(1) is the core mandatory detention provision. It imposes an absolute obligation on officers — the word "must" allows no discretion. If an officer knows or reasonably suspects a person in the migration zone is an unlawful non-citizen, the officer must detain that person.
The standard for triggering the obligation is "knows or reasonably suspects" — this is a lower threshold than proof. A reasonable suspicion does not require certainty; it requires only that there are objective grounds for the suspicion.
Subsections (2)–(4) extend the detention power to other contexts: outside the migration zone (discretionary), at proclaimed ports, and at airports where a person has not been immigration cleared.
A person detained under s 189 remains in detention until they are removed from Australia, deported, granted a visa, or their detention is otherwise lawfully ended. A bridging visa is one mechanism by which a person can be lawfully released from immigration detention pending resolution of their visa status.
Practical effect
Section 189 is one of the most litigated provisions of the Migration Act. The mandatory detention regime it establishes has been the subject of numerous High Court decisions, most notably Al-Kateb v Godwin (2004) 219 CLR 562, which held that detention under s 196 (which requires detention until removal or grant of a visa) could continue indefinitely even where removal was not reasonably practicable in the foreseeable future.
The provision operates automatically: a person whose visa is cancelled under s 116 immediately becomes an unlawful non-citizen under s 5, and an officer who knows this must detain them under s 189(1).
The High Court confirmed in Plaintiff M76/2013 v Minister for Immigration (2013) 251 CLR 322 that the power to detain under s 189 requires actual or suspected unlawful non-citizen status — it is not sufficient that the person's visa status is uncertain.
The 2023 decision in NZYQ v Minister for Immigration (2023) overturned aspects of Al-Kateb, holding that indefinite detention of a person whose removal is not reasonably practicable is not authorised by the Act and is constitutionally invalid.