Consistent with Australia's treaty obligations, the government has been given 180 days to assure the committee that it has acted on the recommendations and taken steps to prevent "similar violations in future". The UN's Human Rights Committee concluded that the continued detention of the refugees, most of them Sri Lankan Tamils, is "cumulatively inflicting serious psychological harm" and in breach of the International Covenant on Civil and Political Rights. The committee's investigation followed a complaint lodged on behalf of the refugees in August 2011 by Professor Ben Saul, of the Sydney Centre for International Law, who said the finding proved the "grave lawlessness" of Australian refugee policies. "It is a major embarrassment for Australia, which is a member of the Security Council and often criticises human rights in other countries. Australia should do the right thing by respecting its international obligations and treating the refugees decently," Professor Saul told Fairfax Media. The committee found that, whatever justification there may have been for an initial detention, the government had not demonstrated on an individual basis that the continuous indefinite detention of the refugees was justified.

"The State party (government) has not demonstrated that other, less intrusive, measures could not have achieved the same end of compliance with the State party's need to respond to the security risk that the adult authors (refugees) are said to represent," it said. It also found that those held were "not informed of the specific risk attributed to each of them". While the committee has consistently found fault with Australia's system of mandatory immigration detention, Professor Saul said this finding went much further. "It is the largest complaint ever upheld against Australia," he said. The UN body traditionally allowed governments wide discretion where issues of national security were concerned, but found 46 cases of illegal detention, 46 cases of no effective judicial remedies for illegal detention and 46 cases of inhuman or degrading treatment in detention. It is believed that at least four of the 46 have since been granted visas after their cases were reviewed. The UN committee is considering a similar complaint from another five refugees with adverse ASIO assessments.

"For the committee to come out and make such stark findings is a pretty firm indication of just how seriously the committee regards these breaches," Professor Saul said. While the Coalition has signalled that it will continue to take a hard line against refugees deemed threats to security, Attorney-General Mark Dreyfus has conceded the need to explore alternatives to indefinite detention of those deemed security threats. "I don't think it's enough to say you can do it, so we will, which has been the approach of successive governments," Mr Dreyfus recently told Fairfax Media. "I think we've got to think through what we are doing to other human beings and think through what principles we are bringing to bear, at all times keeping the security of Australia paramount." Although the government appointed a former judge to review the cases of those in detention after a High Court challenge to their detention succeeded last year, it has not acted on various calls for alternatives to detention to be introduced for those considered security risks. These include a recommendation last October from one of the nation's most senior authorities on security, Dr Vivienne Thom, for ASIO and immigration officials to work on "risk mitigation strategies and conditions" that would enable asylum seekers to be released from indefinite detention.

A spokesman for the Tamil Refugee Council, Trevor Grant, said the UN committee had vindicated the strong belief of many advocates and lawyers that indefinite detention was intolerable in a just society. "The message to the Australian Government is unambiguous here. If its signature on a treaty means anything, it must immediately release these people," he said. The UN committee chair, Sir Nigel Rodley, said the "arbitrary" nature of the detention informed the findings - not national security grounds. “To be able to invoke national security without giving any grounds for this and without giving people any possibility to challenge the determination would permit states to ignore all their international obligations to protect human rights," he said. "They must find a way of reconciling these imperatives."

He said the report was decided in July and finalised in recent weeks according to usual practice and the timing of the release was not political. With Daniel Flitton