Plaintiff M96A is the most recent High Court case to test the constitutional boundaries of Australia’s immigration detention regime. The plaintiffs, a mother and daughter originally from Iran, arrived in Australia by boat in 2013. They qualified as ‘unauthorised maritime arrivals’ under s 5AA of the Migration Act (‘the Act’), and were detained initially at Christmas Island. Subsequently, they were taken to Nauru under s 198AD, and were held in detention there.
In November 2014, the plaintiffs were brought to Australia from Nauru, for the purpose of receiving medical treatment. While undergoing treatment, they were placed in detention, first at Darwin and then at the Melbourne Immigration Transit Accommodation. They challenged this detention in the High Court.
The statutory scheme
Because they had been transferred to Nauru – a regional processing country – the plaintiffs qualified as ‘transitory persons’ under s 5(1) of the Act. Their later transfer to Australia was authorised by s 198B, which authorises the executive to bring ‘transitory persons’ to Australia for a ‘temporary purpose’. In the plaintiffs’ case, this temporary purpose was to receive medical treatment.
Notably, the plaintiffs did not seek to challenge either their removal to or detention in Nauru, or their transfer to Australia. Their only challenge was to their detention while receiving medical treatment in Australia, which they argued was unconstitutional.
This detention was governed by ss 189(1) and 196(1), which provide for the detention of ‘unlawful non-citizens’ within Australia. The plaintiffs were ‘unlawful non-citizens’ because they did not have valid visas authorising their presence in Australia. Section 189(1) requires executive officers to detain unlawful non-citizens. Section 196(1) provides that an unlawful non-citizen detained under s 189 must be kept in immigration detention until he or she is either removed from detention, taken to a regional processing country, deported or granted a visa.
For transitory persons like the plaintiffs, detention typically ends with removal from Australia. This is because s 46B precludes transitory persons from making valid visa applications without written ministerial consent. The plaintiffs had not been granted consent to apply for a visa.
There are two main ways in which a transitory person detained under s 189 can be removed from Australia:
- Where the person no longer needs to be in Australia for the temporary purpose for which they were brought into the country, S198AD requires an officer to take them to a regional processing country as soon as reasonably practicable. Importantly, this duty arises whether or not the temporary purpose has been achieved.
- In circumstances where s198AD does not apply, s 198(1) requires an officer to remove a transitory person, as soon as reasonably practicable, if they request removal in writing. This procedure would, for instance, apply if the transitory person does have an ongoing need to be in Australia for the temporary purpose, but nonetheless requests removal.
The Court examined the constitutional validity of the statutory scheme for the detention of transitory persons, under which the plaintiffs were detained. It looked at two relevant questions, which drew on the approach taken in Chu Kheng Lim and Plaintiff S4:
- Whether the detention was for a constitutionally permissible purpose, and
- Whether the duration of the detention was sufficiently capable of being determined by a court.
All members of the Court answered both of these questions affirmatively, and found that the plaintiffs’ detention was constitutionally valid. There were two judgments: a joint judgment by Kiefel CJ and Bell, Keane, Nettle, Gordon and Edelman JJ (‘the plurality’), and a separate judgment by Gageler J, who agreed with the plurality’s findings, and made some additional comments in obiter regarding jurisdictional facts.
The purpose of detention
The plaintiffs and the defendants divided over two questions:
- How the purpose of the detention of transitory persons should be characterised, and
- The constitutionally permissible purposes for executive detention of a non-citizen.
The plaintiffs argued that the purpose of the detention of transitory persons was identical to the temporary purpose for which they were brought to Australia. In their case, this was the purpose of receiving medical treatment. They further argued that detention for a ‘temporary purpose’, such as medical treatment, was not constitutionally permissible, as it did not fall within any of the three valid purposes identified in Plaintiff S4: removal from Australia, processing of a visa application and determining whether to permit a visa application to be made.
The Commonwealth, by contrast, submitted that the permissible purposes identified in Plaintiff S4 were not exhaustive. It also argued that the purpose of detaining transitory persons such as the plaintiffs was not the temporary purpose for which they were brought to Australia. Rather, the purpose of their detention was to segregate them from the Australian community (which they had no right to enter without a visa) while the temporary purpose was being pursued, and to ensure that they would be available for removal once they no longer needed to be in Australia.
The Court agreed with the Commonwealth’s characterisation of the purposes underpinning the detention. The plurality noted that there were two factors that highlight why the temporary purpose for which a transitory person was brought to Australia was not the same as the purpose of their detention.
First, detention does not need to aid the fulfilment of the temporary purpose. Indeed, the plurality noted that for transitory persons like the plaintiffs, who were brought to Australia for the purpose of receiving medical treatment, detention could well be antithetical to achieving the temporary purpose.
Secondly, the length of detention does not depend upon the temporary purpose being fulfilled. A transitory person can, for instance, ask to be removed from Australia before the temporary purpose is fulfilled, and an obligation to remove them as soon as reasonably practicable will arise under s 198(1).
Notably, the plurality found that the purposes underpinning the detention of transitory persons are the same purposes that apply to ‘all other instances involving unlawful non- citizens under s 189’. Where an unlawful non-citizen is precluded from applying for a visa, their detention is for the purpose of removal. This was the position that the plaintiffs, and most other transitory persons, found themselves in.
In this way, the Court reasoned that the detention of transitory persons in Australia was for the purpose of removal from Australia – one of the three constitutionally permissible purposes recognised in Plaintiff S4. In light of this, the plurality expressly declined to decide whether those three purposes are the only purposes that can underpin the executive detention of non-citizens. This question awaits a later case.
The duration of detention
The plaintiffs’ second argument was that detention of transitory persons by the executive infringed the constitutional separation of judicial power. This was said to be the case because the period that a transitory person would remain in detention could not be objectively determined. The plaintiffs relied on the Court’s statement in Plaintiff S4 that ‘[t]he duration of any form of detention, and thus its lawfulness, must be capable of being determined at any time and from time to time’.
The plurality affirmed this statement from Plaintiff S4, but found that the plaintiffs had misunderstood it. Their Honours held that what is required is the existence of ‘objectively determinable criteria for detention’. In other words:
Parliament cannot avoid judicial scrutiny of the legality of detention by criteria which are too vague to be capable of objective determination. This would include an attempt to make the length of detention at any time dependent upon the unconstrained and unascertainable opinion of the Executive.
All seven judges found that the scheme for the detention of transitory persons specified preconditions that had the unequivocal effect of ending detention. The plurality noted:
One precondition is that detention will come to an end under s 198(1) as soon as reasonably practicable after the transitory person asks the Minister, in writing, to be removed from Australia. Another precondition is that the person no longer needs to be in Australia for the temporary purpose.
The Court found that these preconditions make the duration of detention objectively determinable, even if the precise length of a transitory person’s detention cannot be judged at the outset. Citing Al-Kateb as authority, the plurality noted:
The detention does not become an exercise of judicial power merely because the precondition, and hence the period of detention, is determined by matters beyond the control of the Executive. This will frequently be the case where, for instance, questions arise as to whether it is reasonably practicable to remove a person from Australia.
For these reasons, the Court held that the executive detention of transitory persons was constitutionally valid.
There was some discussion in the hearing over how the question of whether a transitory person has an ongoing need to be in Australia for a ‘temporary purpose’ should be determined. The Commonwealth submitted that this was a matter for an executive officer to determine, while the plaintiffs argued it was a jurisdictional fact, to be objectively determined by a court.
How this question is answered potentially impacts upon the point at which a duty to remove a transitory person from detention arises. However, it was not necessary to determine the point to decide the plaintiffs’ case, as all parties agreed that both plaintiffs had a continuing need to be in Australia to receive medical treatment.
For this reason, the plurality did not rule on this point; however Gageler J did. His Honour held that, as a matter of statutory construction, the question of whether a transitory person needs to be in Australia for a temporary purpose is one that, in the event of a dispute, must be objectively assessed by the courts. His Honour noted that there are established drafting techniques that are used when Parliament intends for a particular power or duty to be activated when the person exercising it holds a particular state of mind. These techniques are used throughout the Act. They are not, however, used in the provisions that regulate the removal of transitory persons. On the contrary, Gageler J said that these provisions ‘[cast] the precondition to the performance of the duty to remove in manifestly objective terms’.