Thulasitharan Santhirarajah, the former head of the Melbourne International College, has spent four years in custody, most of that time awaiting a decision by the federal government on whether to support his US prosecution over alleged links to the Tamil Tigers.

Ms Roxon signed the extradition order in February, sparking a legal challenge by the man's lawyers, who insist he has never been a threat to the US or Australia and that the alleged offences are more political than security-related. A Federal Court judge has heard the case from both sides and is considering his decision.

Mr Santhirarajah, 38, is a Sri Lankan citizen who came to Australia on a short-term business visa and later sought permanent residency. He was arrested in July 2008, amid raids conducted by the Australian Federal Police at the request of the FBI, and accused of having actively supported the Liberation Tigers of Tamil Eelam, which is a listed terrorist organisation in the US. Mr Santhirarajah was initially sought in relation to six charges.

After a magistrate found Mr Santhirarajah eligible for surrender to the US, his wife, Priya, wrote to the government pleading for her husband to be allowed to remain in Australia on humanitarian grounds, and warning that "to consent to Thulasi's extradition will amount to the signing of his death warrant".

"We are certain that if Thulasi is extradited to America to face charges, he will eventually be sent to Sri Lanka and his family will never see him again, as happened in many previous such cases," their petition said.

The Weekend Australian revealed on Saturday that the first Tamil asylum-seeker to be deported from Australia since the end of the island nation's 27-year civil conflict had recanted his prior claims of torture at the hands of the Sri Lankan government.