Indefinite immigration detention is unlawful, the High Court has ruled, upending a controversial decision that has guided the Australian asylum seeker policy for the last two decades.
With a majority of justices in agreement, the court overturned a 2004 determination that ruled unsuccessful asylum seekers who could not be removed to another country could lawfully be held in indefinite immigration detention.
The High Court came to it decision on Wednesday after lawyers for a detained Rohingya man from Myanmar, referred to by the pseudonym NZYQ, argued the 20-year-old ruling was wrongly decided.
Chief Justice Stephen Gageler showed concern about the lack of time frames around indefinite detention.
"The problem here is with the scenario where that which the provision is designed to achieve in fact simply will not occur, cannot occur, at least in the foreseeable future," he told the High Court.
When told some people were less desirable to other countries because of their record or the security risk they may pose, the chief justice noted, "another way of putting that – a less attractive way of putting it – is that they are being kept in detention because of their character".
The original, now overturned, decision involved stateless Palestinian Ahmed Ali Al-Kateb and Iraqi national Abbas Mohammad Hasan Al Khafaji, who had both arrived in 2000.
The duo had applied for Australian temporary protection visas but were rejected and asked to be returned to the Middle East.
However, the government could not reach an arrangement for another country to take them.
The two men had been in the community for 12 months at that point, but the court order determined they should be returned to detention.
Mr Al-Kateb and Mr Al Khafaji were quickly granted bridging visas but others since have not been so lucky.
According to the Human Rights Law Centre, the government holds people in detention for 708 days but there are currently 124 people who have been detained for more than five years, many of whom are stateless or owed protection by Australia.
With this decision, about 90 people held in a similar detention situation to the Rohingya man could soon be released.
Jane McAdam AO, director of UNSW's Kaldor Centre for International Refugee Law, called Wednesday's decision an "important and long-awaited victory for human rights".
"Indefinite detention has always been arbitrary and unlawful under international law," Prof McAdam said.
"For decades, Australia's approach to detention has been completely out of step with that of other democratic countries.
"This will now have to change."
The court will publish its judgment in the coming months.