U.S. Vice President Dick Cheney, on a visit to Australia, agreed to arrange the release of a Guantanamo Bay detainee.

The claim is made by Harper's Magazine, which says Australian Prime Minister John Howard was under pressure in an election year as the continued detention of Hicks without charge was unpopular with the public, and he persuaded Cheney to organise an early release.

A plea deal was allegedly entered into soon after Cheney's return to the United States.

Howard denied the report, saying no deal was entered into and the military commission at Guantanamo Bay decided Hicks's fate. He elaborated saying he made no representations to Cheney in relation to Hicks.

However the U.S. official in charge of the Hicks prosecution in an interview with The Australian newspaper has admitted to claims of political interference in the case.

Speaking to The Australian, former chief prosecutor Colonel Morris Davis said he was subject to continuing high-level political interference in his handling of the Hicks case.

'In my opinion, as things stand right now, I think it's a disgrace to call it a military commission, it's a political commission,' he said.

Harper's quoted an unnamed military official saying 'one of our staffers was present when Vice-President Cheney interfered directly to get Hicks's plea bargain deal'.

'He did it, apparently, as part of a deal cut with Howard,' the official was quoted as saying.

On Tuesday, it was also revealed Australian Federal Police might apply for a control order for Hicks upon his release from Adelaide's Yatala prison at the end of the year, The Australian reported.

Hicks was transferred from Guantanamo Bay in Cuba to Yatala in May to serve a seven-month sentence, which was secured as part of a plea bargain that involved a guilty plea on a single terror offence.

Colonel Davis said the Harper's story 'made as much sense as any other reason I can think of.'

'The deal was significantly more lenient than anything I would have agreed to,' he told The Australian.

Colonel Davis resigned as chief prosecutor in October following a dispute with the legal adviser to the Convening Authority, which runs the U.S. military commissions.

He said on January 9 this year he received a phone call from the General Counsel for the U.S. Department of Defence, Jim Haynes, asking when he could charge Hicks.

Colonel Davis said he told Mr Haynes the charges could be ready two weeks after the Manual for the Military Commissions, which defined the offences, had been produced. He was told that was too long.

Immediately after the phone call, Colonel Davis said he received a second phone call from Mr Haynes's deputy telling him to disregard what he had just been told.

'The deputy said, 'I went in and took a wire brush to (Mr Haynes) and explained he cannot have those kind of conversations with you, so disregard everything he just said',' Colonel Davis said.

However, on January 31, Mr Haynes called again, demanding to know why no charges had been laid. 'He said, 'You told me you'd have charges two weeks after the manual came out. You promised me you'd have charges and I promised other people we'd have charges. Where are the charges?'' Colonel Davis said. He said Mr Haynes wanted others tried with Hicks, presumably to prevent the impression the charges were 'a political solution to the Hicks case.'

He was acting on pressure from higher up, although he told The Australian he did not know from whom.

News of a possible deal has caused a furore in Australia. The country goes to the polls next month, and Howard's Liberal-National Party coalition is faciung defeat. Opposition Leader Kevin Rudd on Wednesday called on the government to come clean over the Hicks affair. "I'm very interested to see what further Mr Howard may have to say on that matter," he told reporters in Melbourne.

"Remember, Mr Howard has said there was no deal. We now have senior American officials saying there was a deal," he added.

Hicks is barred from talking to the media as part of his plea bargain.

Hicks was captured by a 'Northern Alliance warlord' in December 2001, in Afghanistan, and 'sold' to U.S. Special Forces for $1,000.