The Supreme Court of Canada has agreed to hear arguments about the legality of the U.S. military prison at Guantanamo, where Canadian Omar Khadr is being held.

The high court ruled yesterday that it could consider submissions on whether Guantanamo violates international law, dismissing the federal government's objections that the Canadian courts were not the place to examine the actions of the United States.

"In essence, the respondent (Khadr) wants the court to preside over a trial of the Guantanamo trials," the government argued in its submission. "The court should refuse this invitation."

Khadr is now the sole Western detainee remaining at Guantanamo, and Canada has come under international pressure to demand his repatriation.

Now 21, Khadr was 15 when he was shot and captured in Afghanistan in July 2002 and accused of throwing a grenade that killed Delta Force soldier Christopher Speer. The Pentagon has charged him with five war crimes, including "murder in violation of the laws of war."

The Supreme Court has already scheduled a hearing for Wednesday, in which the central questions are whether Khadr's lawyers are entitled to evidence from Canada that could help in his defence at Guantanamo and if the Canadian officials who travelled to the base to interrogate him in 2003 and 2004 breached his constitutional rights.

But in hearing arguments about whether Khadr's rights were violated in Guantanamo, the court agreed in its unanimous ruling yesterday that it could consider the actions of American officials and the conditions at the U.S. Navy base in Cuba, which in essence also puts Guantanamo Bay on trial.

"Canadians should be pleased about that because regardless of what the court decides, I don't think anyone can question that the Supreme Court has a role in overseeing government action, in particular something as important as the rights and freedoms of a Canadian who has been imprisoned abroad," said Michael Byers, who holds a Canada Research Chair in global politics and international law.

"The larger issue at stake is whether or not the Canadian government can continue to get away with an apparent – not only disregard for the rights of a Canadian citizen – but also alleged complicity in his plight. This is why we have the checks and balances of a democratic system with an independent judiciary."

The court also rejected the government's bid to block human rights groups from raising points of international law in their intervention in the case.

University of Toronto law professor Audrey Macklin, who will represent the university's law clinic and Human Rights Watch at the hearing, said the court's rulings on these points may force the government to defend its actions.

"Certainly, what the Supreme Court of Canada says about the legality of Guantanamo Bay and the actions of Canadian officials with respect to a citizen there, will reverberate in the political sphere in terms of bringing greater attention to, and a requirement of justification by the government of Canada about why it refuses to intervene," Macklin said.

Canada sent agents from the Canadian Security Intelligence Service and an official with the intelligence division in the foreign affairs department to interrogate Khadr in the two years after his capture. The purpose of the visits was to collect intelligence, since the U.S. would not permit consular visits for detainees.

Khadr's Canadian lawyers, Dennis Edney and Nathan Whitling, have argued that these interrogations – and turning over the information gleaned by the Canadians to U.S. officials – violated Khadr's constitutional rights.

They also argue that the government's refusal now to hand over the complete notes from the interrogations further breaches his right to fair trial.