The Bush administration says Guantanamo prisoners have no constitutional right to challenge their detention before US federal judges, and the lawsuits by hundreds of detainees must be dismissed.

The detainees include Australian terror suspect David Hicks, 31, who has been held at the US military camp at Guantanamo Bay, Cuba, since he was arrested in Afghanistan in 2001.

In papers filed with a US appeals court in Washington, Justice Department lawyers gave their most detailed argument yet that the cases must be dismissed because of the tough anti-terrorism law signed by President George W Bush last month.

Lawyers for the prisoners have argued the new law does not give the US government the power to arrest suspects overseas and imprison them indefinitely without any charges and without allowing them to challenge their detention in US court.

They say a provision of the law unconstitutionally suspends the right under habeas corpus, a long-standing principle of American law, for detainees to contest their imprisonment.

Justice Department lawyers disagreed.

"There is no constitutional habeas right for an enemy alien held outside the United States to challenge his detention," they said.

"No actual habeas rights have been suspended."

After Bush signed the Military Commissions Act of 2006 into law, the Justice Department told federal district court judges they no longer have jurisdiction over some 200 cases covering more than 400 prisoners at the US military base at Guantanamo Bay in Cuba.

Department lawyers told the appeals court the new law and a similar law, the Detainee Treatment Act that Congress approved late last year, provide "an unprecedented level of judicial review for the claims of the enemy aliens held at Guantanamo."

They said the prisoners received a military proceeding, called a Combatant Status Review Tribunal, to determine if the detainee has been rightfully deemed to be an unlawful enemy combatant.

Those proceedings can be appealed directly to the appeals court, but the prisoners are not entitled to a sweeping factual inquiry by a federal district court judge, the lawyers said.

Those cases must be dismissed.

The appeals court is expected to rule later this year or early next year, but any decision likely will be appealed to the US Supreme Court, which would have the final word on the law's constitutionality.

The law was prompted by a Supreme Court ruling in June that said Bush lacked the legislative authority in setting up his first system of military commissions after the September 11 attacks.

That prompted Bush to go to Congress to get authority under the new law authorising tough interrogation and prosecution of terrorism suspects under a new system of military commissions.

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