The Department of Foreign Affairs says it is not aware of allegations that Guantanamo Bay detainee David Hicks has refused to meet consular officials because he believes he has been punished after previous visits.

Officials from the department had earlier told a Senate hearing that Hicks did not give any reasons when he refused to meet the Australian Consul-General at Guantanamo Bay in September.

The hearing has now been told that Hicks's US military lawyer, Major Michael Mori, says his client believes he has been punished after making complaints during previous consular visits.

The department's first assistant secretary, Rod Smith, has told the hearing Maj Mori has not raised those concerns with Australian officials.

"It would be a matter of very great concern to us if Australians in detention overseas were punished for simply drawing to the attention of consular officials concerns that [they] have about the conditions of their detention," Mr Smith said.

The hearing was told the current charges against Mr Hicks have lapsed and the regulations governing the new military commissions will come into force in January.

Queensland Labor Senator John Hogg has questioned why a firm date cannot be given for new charges to be laid.

"Well, it's not very reassuring for Mr Hicks to be incarcerated and have no prospect as to when he might be charged under this new regime," Senator Hogg said.

"Surely the American authorities can be pressed to give some indication as to when charges might be laid."

A senior legal adviser with the Department of Foreign Affairs, Penny Richards, told the hearing US officials have been urged to lay new charges against Hicks as quickly as possible.

"The Government does remain very concerned about ongoing delay and has made numerous representations to the US about these concerns," Ms Richards said.

• David Hicks Case Information

Amnesty International has accused the Australian government of abandoning terror suspect David Hicks and doing nothing to ensure sure he gets a fair trial.

• David Hicks Case Information

LAWYERS for dozens of Guantanamo Bay detainees have asked a US appeals court to declare a key part of George Bush's new military tribunal law unconstitutional.

Mr Bush gave the military that authority earlier this month when he signed a new law that sets up military commissions to hold trials for foreigners designated as "enemy combatants."

Mr Bush hailed the law as a crucial tool in the war on terrorism and said it would allow prosecution of several high-level terror suspects.

Lawyers for more than 100 detainees who will be locked out of the court system under the new law asked the appeals court to let them keep their legal challenge going in civilian courts.

They said the framers of the US Constitution never would have permitted the government to hold people indefinitely without charging them.

"Persons imprisoned without charge must retain the right to obtain a court inquiry into the factual and legal bases for their imprisonment," lawyers wrote.

This argument echoes a Supreme Court ruling in June, when justices declared that the Bush administration's system of trying enemy combatants violated US and international law.

Within weeks, the president convinced Congress to pass a new law setting up military commissions and barring detainees from using the civilian court system.

Shortly after the new military commissions law was signed, the Justice Department told hundreds of detainees that their cases in the US courts had been rendered moot.

Seven retired federal judges from both the Republican and Democratic parties filed the legal briefs in the detainees case before the Washington appeals court, arguing that the military commissions law would allow authorities to use evidence obtained by torture.

Although the law prohibits torture, the judges said the military has not addressed torture claims made by detainees. The judges also argued that the new law illegally strips courts of the power to question military decisions about the detainees' torture claims.

The Justice Department has until November 13 to respond to the detainees claims.

Adelaide-born Hicks has been held in Guantanamo Bay since soon after he was captured with Taliban forces in Afghanistan in late 2001.

US authorities charged him with conspiracy to commit war crimes and attempted murder by an unprivileged belligerent and aiding the enemy, but the charges were dropped after the Supreme Court ruling.

• David Hicks Case Information