The broad reach of the federal government’s power to detain a person under s 189 of the Migration Act 1958 (Cth) is self-evident. Section 189 requires the detention of a person whom an immigration department official “knows or reasonably suspects” (emphasis added) is an “unlawful non-citizen”.
The breadth of this power of detention is underlined by the fact that an immigration official’s “subjective state of mind” is the decisive factor. The High Court made this clear in Ruddock v Taylor  HCA 48 when it decided that s 189 extends to “the case where an officer is subjectively convinced that a person is an unlawful non-citizen but later examination reveals that opinion to have been legally flawed”.
The consequences for the person detained in these circumstances are grim, including possibly many months in detention – as has happened on a number of occasions. In Al-Kateb v Godwin  HCA 37, the High Court accepted that, under s 189, a person might be detained indefinitely if deportation from Australia was not otherwise “practicable”.
While an immigration official’s subjective assessment of a situation will determine whether a person is detained, it is not an unconstrained exercise. This is implicit in Ruddock v Taylor, where the majority of the Court (Gleeson CJ, Gummow, Hayne and Heydon JJ) noted that the immigration officials concerned (there were two instances of detention of the same person) had each “been provided with what, on its face, appeared to be a regular and effective decision of the Minister to cancel the respondent’s visa”. The majority judgment goes on to say that the two officials also checked that the person concerned held no other visa, and concluded that the officials’ reasonable suspicion that the person was an unlawful non-citizen, followed “inevitably”.
In effect, in the circumstances it seems that, for the High Court, the officials had no real choice but to find the person concerned to be an unlawful non-citizen and detain him. The appearance that a visa cancellation was lawful may therefore be the foundation for a valid exercise of the official’s subjective determination.
If the subjective exercise involved in an immigration official determining whether a person is an unlawful non-citizen is, in reality, constrained, this suggests in direct inverse proportion that the Minister’s effective discretion is correspondingly enlarged. The Court in Ruddock v Taylor can be said to have endorsed that conclusion by deciding that detention on the basis of the Minister acting unlawfully in cancelling a person’s visa might itself (the detention) be lawful.
The official is potentially the cover for a Minister’s unlawful exercise of their visa cancellation power. After all, it is the official who subjectively decides that someone is an unlawful non-citizen and must be detained, not the Minister.
Does the reasonable suspicion test then enable a Minister to sidestep ministerial responsibility? Could a Minister improperly and deliberately cancel someone’s visa, perhaps out of a political motivation, knowing that the official will be the fall guy?
The operation of s 189 of the Migration Act 1958 is considered in updated The Laws of Australia Subtitle 21.6 “Justice”.
For more information about The Laws of Australia, click here.