Former Guantanamo Bay inmate David Hicks has welcomed a UN human rights committee ruling that the Australian government violated his rights by keeping him in jail for months under a transfer deal with the US.

Hicks’ jailing was despite the fact the sentence imposed on him was the result of a “flagrant denial of justice”, Fabian Salvioli, chair of the UN human rights committee, said on Tuesday.

“It’s not the first time I’ve had my abuse claims upheld,” Hicks told Guardian Australia.

“It also shows the Australian government’s complicity and the power they had as far as keeping me in Guantanamo and choosing to have me released.”

He flagged further legal action against the Australian government “to make them pay for my medical costs”, which he said still hampered his ability to work.

The findings by the committee, which is composed of 18 independent experts, came after considering a complaint brought by Hicks about his treatment by Australia. The finding was adopted, with two committee members dissenting, in November and published on Tuesday.



It found a violation had occurred but ruled that the Australian government was not obliged to make reparation payments to Hicks.

“Transfer agreements are important because they allow prisoners convicted abroad to serve their sentences in their own country,” Salvioli said.



“But states should not carry out a sentence if there is ample evidence that the trial clearly violated the defendant’s rights, as was the case with Mr Hicks.”

The decision to continue to jail Hicks as a result of the transfer deal “constituted a disproportionate restriction of the right to liberty” in violation of the international covenant on civil and political rights, the committee found.



Hicks was arrested in Afghanistan in 2001 and sent to the US naval base at Guantánamo Bay in Cuba in January 2002.



In March 2007, after pleading guilty under a plea agreement, he was convicted under the US Military Commission Act 2006 with “providing material support for terrorism” and given a seven-year sentence, most of it suspended.



He was transferred in May 2007 to Australia, where he served the remaining seven months of his sentence in prison.



Salvioli said by the time Hicks was transferred, there was a lot of information available that raised serious concerns about the fairness of the procedures by the US military commission. “That should have been enough to cast doubt among the Australian authorities as to the legality and legitimacy of the sentence imposed on him,” he said.

Australian officials had also visited Hicks at Guantánamo 21 times and were in a good position to understand the conditions under which he was held and tried.



The commission wrote that in order to escape the violations to which he was subjected in Guantánamo, Hicks “had no other choice than to accept the terms of the plea agreement that was put to him”.



“It was therefore incumbent on [Australia] to show that it did everything possible to ensure that the terms of the transfer arrangement that had been negotiated with the United States did not cause it to violate the covenant.”



The committee said that as a party to the ICCPR, Australia was “obliged to make full reparations to individuals whose rights have been violated”.



But in Hicks’ case, Australia’s actions were intended to help him and did mitigate the harm he would have suffered had he remained in US custody, and so the finding of a violation was sufficient reparation, the committee ruled.

Australia objected to the complaint, saying there was no duty under the ICCPR to investigate allegations of torture relating to conduct outside of a state party.

Two dissenting committee members, Sir Nigel Rodley and Dheeruijall Seetulsingh, sided with Australia, saying that the committee’s finding was dismissive of Hicks agreeing to the transfer deal and implied that Australia should have breached its agreement with the US and freed Hicks on arrival.

“Such a course of action would make a complete mockery of transfer agreements and would be in violation of all international legal obligations and diplomatic relations,” Seetulsingh said. “That would not safeguard human rights and cannot be the purpose of our Covenant”

Hicks successfully appealed against his terrorism conviction last year,in a unanimous ruling of the US court of military commission review.

Then prime minister Tony Abbott refused to apologise to Hicks, saying he had been “up to no good on his own admission” in Afghanistan in 2001, and a spokesman for John Howard, who was prime minister when Hicks was detained and later brought back to Australia, said at the time that Hicks: “revelled in jihad. He is not owed an apology by any Australian government.”

Hicks confronted the attorney general, George Brandis, at a human rights event in 2014 and said he was tortured “in the full knowledge of your party”.

After his exoneration, the 40-year-old later told Guardian Australia that it “feels good that I’m an innocent man,” adding: “I’m disappointed that even though the American and Australian authorities were aware of my innocence from day one, I still have to go through years of torture that ruined my life for no reason, for political purposes.”

Malcolm Turnbull has yet to comment on the committee’s findings.

“The UN Human Rights committee is the world’s premier body for interpreting international human rights law and Australia has agreed to abide by that law,” Human Rights Law Centre director of advocacy and research Emily Howie said.

“So you would hope and expect that Australia’s prime ministers do take these decisions seriously.”

• Australian Associated Press contributed to this report