The opposition Labor Party on Wednesday asked the government to explain whether the release of an Australian terror suspect held in U.S. custody for three years at Guatanamo Bay (search) is linked to his claims he was tortured.

The government announced Tuesday that Sydney resident Mamdouh Habib (search), who was born in Egypt, will be released without charge from the U.S. military camp in Guantanamo Bay, Cuba, even though the United States still belbib's court affidavits was made public in which he said that after he was arrested in Pakistan (search) he was transferred to Egypt, where he was tortured with beatings and electric shocks and was nearly drowned.

His lawyers said they believed the United States had asked Pakistan to send Habib to Egypt knowing he would likely be tortured there. Egypt has not commented on the allegations.

Habib's lawyer, Stephen Hopper, said Wednesday that Habib was under U.S. supervision in Pakistan and Egypt.

Labor's spokeswoman on legal matters, Nicola Roxon, said the government must explain whether the affidavit had prompted the American decision to release Habib.

"We think it's very suspicious that Mr. Habib is being released so quickly after those allegations of torture were made last week, and would like to know if it has anything to do with his release," Roxon told Sky television.

"We know that the Americans are sensitive to those allegations. If there were some truth in them, it might be a reason for releasing him," she said.

Prime Minister John Howard said the United States had its "reasons" for releasing Habib but would not elaborate except to say that the 48-year-old father of four would remain a "security interest" in Australia.

The United States has said Habib confessed that he knew in advance of the al-Qaida plot to fly hijacked airliners into buildings in Washington and New York, and that he had trained some of the hijackers in martial arts. His attorneys claim the confessions were coerced from him.

Habib's torture allegations were part of an affidavit filed in the U.S. District Court for the District of Columbia in November as part of an application to have him released from Guantanamo Bay. They were only made public last week.

Amnesty International said the Australian government must fully investigate Habib's torture allegations even though the U.S. case against him was likely to be dropped.

"Our concern is that those allegations are taken seriously," Amnesty's Australian campaign manager Andrew Beswick said.

"We believe that there should be a thorough investigation of those allegations to assure the Australian people of the level of knowledge that the Australian government has of those activities," Beswick said.

The Pentagon released a statement maintaining that Habib and four Britons who are also to be released are enemy combatants, but that the Australian and British governments would try to prevent them from engaging in terrorism in the future.

The Australian government said that the only other Australian captive at Guantanamo Bay, David Hicks, would face trial by a U.S. military commission in Cuba in March.

Australia-born Hicks, 29, is charged with conspiring to commit war crimes, aiding the enemy and attempting murder by firing at U.S. or coalition forces while fighting for Afghanistan's ousted Taliban regime in late 2001.