Mandatory detention
Statutory definition
Section 189 of the Migration Act 1958 (Cth) requires that 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. Section 196 provides that an unlawful non-citizen detained under s 189 must be kept in immigration detention until they are granted a visa, removed, or deported.
Explanation
Australia's mandatory detention regime is one of the most stringent in the world. Unlike the discretionary detention systems in most comparable countries, s 189 mandates detention — the officer cannot choose to release the person without legal authority.
The constitutional validity of mandatory detention was upheld by the High Court in Chu Kheng Lim v Minister for Immigration (1992) 176 CLR 1 on the basis that it is not punitive detention but administrative detention for the purpose of removing the person from Australia.
The duration of detention was held in NZYQ v Minister for Immigration (2023) 97 ALJR 1296 to be constitutionally limited — detention that is no longer reasonably necessary for the purpose of removal (because removal is not reasonably practicable in the foreseeable future) cannot be sustained.
How this term is used
The NZYQ decision (November 2023) resulted in the release of approximately 140–150 detainees who could not be removed. The Government responded with bridging visa and supervised release arrangements. The decision significantly changed the practical operation of the mandatory detention regime for long-term detainees.