Nauru centre opening has 'dramatic effect' on detention challenge, court told

Nauru’s decision to fully “open” its immigration detention centre just days before the Australian high court heard a challenge against offshore processing has emerged as a core element of the government’s defence.

Allowing asylum seekers to move around the Pacific island 24 hours a day had “a dramatic effect” on the legal standing of the Bangladeshi woman who was seeking to prevent her return to Nauru, the Australian government’s lawyers told the court on Wednesday.

The two-day hearing – due to continue on Thursday – was told that the challenge had the potential to dismantle the system of offshore processing supported by the main parties of Australian politics.

The lead case involves a Bangladeshi woman who was on a boat intercepted by Australian officers in October 2013 and was detained on Nauru from January 2014 until August 2014, when she was brought to Australia for medical treatment and subsequently gave birth to a child. The baby is now 10 months old.

The woman’s lawyers argued the Australian government “funded, authorised, procured and effectively controlled” the detention on Nauru, but this was not authorised by a valid Australian law or section 61 of the constitution.

Ron Merkel QC, acting for the asylum seeker, said the day-to-day operation was “an Australian endeavour” and the new open-centre arrangements could be withdrawn at any time in future.

But Australia’s solicitor general, Justin Gleeson SC, rejected the claims, saying it would be “extraordinary” for the court to find that Nauru was “our dependency or our territory” rather than a sovereign nation.

He said Merkel was seeking “a constitutional dismantling of regional processing in any circumstance where the other country chooses to detain people while the [refugee] claims are being processed, the very thing that can validly occur in Australia”.

Gleeson said the person who brought the legal challenge would no longer face detention if she returned to Nauru. He said the new visa conditions continued to set the regional processing centre as “the designated place of residence”, but did not stop anyone from leaving the site at any time.

“In no meaningful way could that be described as detention,” he said.

Gleeson said that “in one sense” Nauru had “given him [Merkel] what he wants” – a reference to the recent announcement that detainees would be free to leave the centre at any time of the day, seven days a week.

One of the seven high court judges, Stephen Gageler, asked Gleeson whether he had invited the court to find that the change in Nauruan law was associated with the commencement of the present legal proceedings.

The solicitor general replied that on the material before the court, it was known that the system had changed and the timing of the decision but “we know precious little more than that”. He added that the change “has a dramatic effect on the plaintiff’s legal rights”.

A document used as a guide for staff to answer detainee questions, obtained by Guardian Australia, shows that people on Nauru have been told to expect no change in their living circumstances for now.

It said those found to be refugees “will be living alongside people who have not been found to be refugees or who have not yet received a decision”, although new accommodation was set to be built.

The immigration minister, Peter Dutton, had welcomed the Nauru government’s actions on Monday, but played down any link to the forthcoming high court case.

“It’s worked progressively to the announcement today, so it’s not just an announcement 48 hours, as you say, before a court case,” he told the ABC’s Lateline program on Monday.

Nauru’s shift to an open-centre arrangement is the second substantial change to have a potential bearing on the case.

The case began with an application filed on 14 May for an order to prevent Dutton from taking steps to return the Bangladeshi woman to Nauru.

In June, the Australian government – then led by Tony Abbott – rushed legislation through the federal parliament to retrospectively clarify the commonwealth’s powers to fund regional processing centres.

The legislation – which won support from the Labor party – inserted a new section into the Migration Act, backdated to August 2012, saying that the commonwealth may “take, or cause to be taken, any action in relation to” regional processing arrangements.

The new section, known as 198AHA, also declared the commonwealth could “make payments, or cause payments to be made, in relation to the arrangement or the regional processing functions of the country” or “do anything else that is incidental or conducive to the taking of such action or the making of such payments”.

The Australian Human Rights Law Centre, which is representing the Bangladeshi woman and says it is acting for about 200 other asylum seekers who were brought to Australia temporarily, pushed ahead with the case.

The centre’s director of legal advocacy, Daniel Webb, said a question now before the court was whether that was a constitutionally valid law.

“Irrespective of these changes, there remain important and untested constitutional questions about the power of the Australian government to pay and to control the detention of innocent people in other countries,” he said outside court on Wednesday morning.

Webb said Australian law clearly gave the government some power to detain people in Australia and remove people from the country “but it is an altogether different thing to fund and control the detention of those people in other countries. It is that funding and that detention that this case challenges.”

The court has been asked to consider whether the commonwealth and the minister’s actions had been authorised by section 61 of the constitution, which covers the extent of executive powers.

The court has also been asked to consider whether the actions were authorised by section 198AHA and whether it is valid, and other financial framework laws.

Transfield Services, a detention centre operator whose contract with the federal government is in the spotlight, is the third defendant in the case, after the immigration minister and the commonwealth.