Major Michael Mori, the US Marine lawyer who will defend Adelaide-born Hicks in the military commission, said the presentation of evidence gained through torture highlighted the flaws of the judicial system to be used to try "war on terror" suspects.

Earlier this week, a leaked report by the International Committee of the Red Cross claimed the American military had used psychological and physical coercion "tantamount to torture" on detainees.

In a further development, the US government admitted in a Washington court for the first time that its military panels reviewing the detentions were allowed to use evidence gained by torture in deciding whether to keep detainees at Guantanamo Bay.

Major Mori said under the rules of the military commissions - a system last used in 1945 that has been resurrected by the US government to try terrorist suspects - evidence gained through torture could not be challenged by the defence.

Major Mori is in Australia this week preparing for Hicks' trial next year, including meetings in Canberra with the Attorney-General's Department and Australian Federal Police.

Hicks, 29, has been held on Guantanamo Bay, Cuba, for three years since he was captured with Taliban forces in Afghanistan in late-2001.

He is accused of fighting with the Taliban against US and coalition forces.

Hicks has pleaded not guilty to attempted murder, aiding the enemy and conspiracy to attack civilians, commit terrorism and destroy property.

Major Mori saw Hicks at Guantanamo Bay about 10 days ago.

He said Hicks was "hanging in there".

Hicks' trial, originally set for early January, is likely to be postponed again after a US court last month threw into doubt the legality of military trials of terrorism suspects and suggested they should be covered by the Geneva Convention.

Major Mori said he was prohibited from commenting on whether Hicks had been tortured, but confirmed he had been physically assaulted in US custody.

Major Mori said lawyers would try to challenge the credibility of evidence gathered under duress, but he was not optimistic.

"This military commission system is designed to allow evidence that could've been obtained under torture to be used as evidence against people," he said.