The Rule of Law requires that all, including the legislative, executive and judicial branches of government, are subject to the law. But what is the relevant law to which all are subject? In Plaintiff S195/2016 v Minister for Immigration and Border Protection (‘Plaintiff S195/2016’) the High Court emphatically and unanimously declared that the laws to which the constitutional powers of the Australian legislative and executive arms of government were subject does not include the laws of other sovereign nations. It follows that a finding that the transfer and detention of Australian asylum seekers on Manus Island (in the northern province of Papua New Guinea) was unlawful under Papua New Guinea law, did not affect the constitutional validity of Commonwealth executive powers to secure and fund the detention of those people. Although the High Court’s decision is not surprising given similar declarations in the past to the effect that international law does not constrain the validity of constitutional powers, the decision does reinforce the vulnerability of ‘aliens’ under our Constitution where constitutional powers remain to all intents and purposes largely unfettered. This post explores this vulnerability in respect of that most significant protection afforded by the law: the protection against unlawful deprivation of liberty.

The international law context: The ruling of the PNG Supreme Court in Namah v Pato

The challenge to the executive power of the Commonwealth in Plaintiff S195/2016, and the question as to the Australian constitutional impact of foreign determination of illegality, arose following the ruling of the Papua New Guinea Supreme Court in Namah v Pato. In that case, the PNG Leader of the Opposition brought an action challenging the lawfulness of the conditions by which Australian asylum seekers resided and were detained at the Manus Island Processing Centre (‘MIPC’) pending processing of their asylum claims. The Australian and PNG governments had previously entered into arrangements (essentially, engaging in relations with another country) for the relocation of unlawful maritime arrivals (‘UMAs’) to Australia and the processing of their asylum claims by PNG. The lawfulness or otherwise of these arrangements, unsurprisingly given that they involved executive prerogative powers, were not considered in the Supreme Court decision.

There were essentially three main grounds of challenge. First, the lawfulness of the administrative arrangements to bring ‘people of different nationalities’, who had sought asylum in Australia to PNG. These arrangements chiefly concerned Ministerial declarations under the PNG Migration Act providing for the lawful entry and presence of the asylum seekers as temporary residents at the MIPC pending the determination of their refugee status. Second, that their detention and the conditions under which they were detained on Manus Island was contrary to their constitutional rights, particularly s 42 of the PNG Constitution guaranteeing the liberty of any person within PNG’s territorial jurisdiction. Third, that the circumstances of their detention were such that neither constitutional exception providing: for lawful deprivation of liberty for migration purposes; or for ‘purposes of holding a foreign national under arrangements made by Papua New Guinea with another country’ were applicable. The latter exemption was a recent amendment to the PNG Constitution that the Supreme Court found unconstitutional for failing to abide by substantive and procedural requirements for amendment of constitutional ‘rights’ provisions.

The PNG Supreme Court was unanimous in its decision that the detention and conditions suffered by the asylum seekers were in breach of PNG’s Constitution, and that the PNG executive had acted beyond power. The Australian and PNG governments were ordered to:

forthwith take all steps necessary to cease and prevent the continued unconstitutional and illegal detention of the asylum seekers or transferees at the relocation centre on Manus Island (at [74]).

and to cease and prevent the continued breach of their constitutional rights. In September 2017 the Victorian Supreme Court approved a $70 million class action settlement for over 1,000 current and former detainees on Manus Island, reportedly in respect of the conditions by which they were detained. The Commonwealth has indicated it will close the centre by 31 October 2017. 

The High Court in Plaintiff S195/2016

The decision in Namah v Pato was handed down in April 2016. In August 2016, proceedings were commenced in the High Court concerning a challenge to Commonwealth executive powers with respect to the MIPC arrangements in light of the decision in Namah v Pato. The central issue of Plaintiff S195/2016 concerned the effect, if any, of Namah v Pato on the constitutional validity of Commonwealth executive powers with respect to the MIPC arrangements. The plaintiff, an Iranian citizen held in detention in the MIPC who had been advised that his claim for refugee status was rejected and issued with a Notice of Removal, revoking his special visa, has declined to return to Iran. He continues to face a restriction on his liberty with no reasonable prospect of removal from Manus Island within a reasonable time.

One of the arguments in the action was that the laws of PNG operate to limit the reach of the executive powers of the Commonwealth, as part of the rule of law. It was argued that given that the detention of the Australian asylum seekers on Manus Island was unconstitutional and unlawful under PNG law, the Commonwealth was therefore not constitutionally authorised to engage in activities with respect to the MIPC.

The High Court in a brief, unanimous decision peremptorily rejected this contention.

The High Court has previously upheld the validity of legislative schemes under the Migration Act 1958 (Cth) to regulate the entry and removal of UMAs from Australia, and to establish offshore centres for the processing of their refugee claims, as valid exercises of the Aliens power under s 51(xix) of the Constitution. Plaintiff M68/2015 v Minister for Immigration and Border Protection (‘Plaintiff M68/2015’) concerned a challenge to a regional processing arrangement with Nauru, similar to that with PNG. The Commonwealth was granted statutory powers, inter alia, ‘to take or cause to be taken, any action in relation to the arrangements for the regional processing functions of the country’. These powers were characterised as incidental to the regional processing framework provided by the Act, that were ultimately reliant for their validity on administrative arrangements between Australia and Nauru done in the exercise of non-statutory executive powers.

The Plaintiff’s First Argument: Effect of the PNG Decision on the Australian Statute

In Plaintiff S195/2016 an argument was made that the administrative arrangements between Australia and PNG were void ab initio given the decision of the PNG Supreme Court in Namah v Pato. Therefore the operation of s 198AHA of the Migration Act 1958 (Cth) which provided the Commonwealth with statutory authority to engage in arrangements with respect to the MIPC was not triggered. There was a cascade of arrangements with PNG done in the exercise of the Commonwealth’s non-statutory and prerogative powers, including a Prime Ministerial agreement, MOUs, and regional processing and settlement arrangements. In a combination of a deferential approach to the exercise of executive powers, and statutory construction, the High Court held that the fact that arrangements had been entered into by the Commonwealth with PNG was enough to trigger the statutory power, even if the Regional Resettlement Agreement and the MOU went beyond the power of the PNG government under their Constitution. The impugned provisions then provided the ‘statutory capacity and authority for the Executive to take action’, but significantly, ’were silent on the matter of the lawfulness of that action.’ In any event, the PNG Supreme Court decision did not hold that PNG’s arrangements with Australia were unlawful.

The Plaintiff’s Second Argument: Breach of the Rule of Law

A second, novel argument advanced by the plaintiff concerned the application of the rule of law as far as it requires that the Commonwealth adhere to the law. The argument proposed a ‘broad principle’ required of the Constitution that the Legislative and Executive powers of the Commonwealth were not constitutionally authorised to engage in activities in another country that were unlawful according to the domestic law of that country. Those powers were valid when entered into for legal purposes only. The values and assumptions underlying this interpretation of the rule of law concerned the need for coherence between laws in the domestic and international spheres that are respectful of the legality of activities in another sovereign state, and that support the comity of nations. In oral argument, counsel for the plaintiff argued:

In our submission, it is somewhat internally contradictory to regard the Australian Constitution as establishing a rule of law for our nation, yet capable of giving power to committing acts in other countries which are contrary to the law of that nation.

The opinion of Murphy J in A v Hayden (1984) 156 CLR 532 was given in support.

Neither the Commonwealth nor any of its Ministers, officers or agents, military or civilian, can lawfully authorize the commission by anyone in another country of conduct which is an offence against the laws of that country and is not authorized by international law (for example, by the laws of war). Whether Parliament could empower such authorization does not arise for decision; it has never purported to do so. Under our Constitution and laws, Australia is a law-abiding member of the community of nations (at [4]).

Before moving to the High Court’s brief rejection of this argument, it is necessary to elaborate a little further on the illegality in issue. This concerned the deprivation of liberty of the plaintiff, as determined by the PNG Supreme Court in Namah v Pato, and whose liberty was still restricted for the purposes of removal from PNG. Strictly speaking, the PNG Supreme Court decision itself did not concern the constitutionality of the Commonwealth’s actions, and made no determination on whether Australia engaged or participated in detaining the asylum seekers on Manus Island. Under the Australian Constitution, there is a limit on the executive power to detain arising from the separation of judicial powers doctrine. In Plaintiff M68/2015, the statutory power to exercise ‘restraint over the liberty of a person’, for the purposes of arrangements associated with the regional processing scheme, was found not to impermissibly infringe this Chapter III limit. This was on the basis that a majority of the High Court found the facts did not support a finding that the Commonwealth was engaged in detaining the plaintiff outside of Australian territory.

The Chapter III limit on Commonwealth executive power was referred to by Justice Higgins, an Australian judge who, together with Justice Kandakasi, gave a written opinion for the Supreme Court in Namah v Pato. Justice Higgins considered that the Chapter III limit was ‘equally applicable to determining the rights conferred upon asylum seekers transferred to Manus Island by virtue of an agreement with the Australian Government’ (at [89]). That is, the legality of the detention was subject to review under Australian law, although His Honour does not suggest this was a matter for the Supreme Court. He does however appear to suggest that a lawful purpose under Ch III, being for the determination of ‘whether to permit a valid application for a visa’ (at [88]) was in play. A further observation was provided. Given the finding that the asylum seekers had been deprived of their personal liberty otherwise than for purposes not authorised under the PNG Constitution, deprivation of liberty might still be available under s 42(9) of the PNG Constitution, if the Manus Island detainees were found to be ‘in transit’ through PNG, while under the ‘custody of another country’. That country being Australia. No finding was made on this point.

The High Court made short work of the broad principle proposed by counsel for the plaintiff, by invoking the orthodox approach to construction of the executive power of the Commonwealth recognised in s 61 of the Constitution as one circumscribed by the text and structure of the Constitution. That text and structure, neither expressly nor by implication, required that the legislative and executive power of the Commonwealth was to be constitutionally limited by what was illegal under the law of another country:

[W]hat is telling is that the plaintiff could marshal no authority to support it and made no attempt to anchor it to the text or structure of the Constitution. The course of authority in this Court leaves no room for doubt that neither the legislative nor the executive power of the Commonwealth is constitutionally limited by any need to conform to international law. Equally there should be no doubt that neither the legislative nor the executive power of the Commonwealth is constitutionally limited by any need to conform to the domestic law of another country (at [20]).

It should be observed, however, that the text and structure of the Constitution provides a sparse framework for determining the validity of constitutional powers especially when it comes to particular classes of people, including aliens. Attempts to limit these powers as a manifestation of the rule of law that takes heed of international law and the legality of actions with other sovereign nations may be drawing a long bow.

Nonetheless, when we consider that early High Court doctrine drew upon international law to substantiate the right of a sovereign nation to expel or deport aliens, parliamentary supremacy aside, why is it improper to consider both our international legal obligations and those of other sovereign nations when dealing with what is essentially a matter of international concern? Both Australia and PNG are signatories to the 1951 Refugees Convention and its 1967 Protocol and disapprobation by the UNHRC with respect to the detainees on Manus Island should mean something. In this frame, one cannot avoid pondering the irony that our right as citizens to sit in our Federal Parliament under s 44(i) of the Constitution may prove to be largely determinative of the citizenship laws of other sovereign nations.


Sue Milne is a Lecturer and PhD candidate at the University of South Australia.

Suggested citation:  Sue Milne, ‘Aliens, Executive Power, and the Rule of Law’ on AUSPUBLAW  (16 October 2017) <>