Opposition MPs are demanding to know what the government knew of Afghan detainee abuse allegations, focusing Monday on an Afghan report that says hundreds of prisoners were tortured by local intelligence officials.

During question period in the House of Commons, NDP Leader Jack Layton pointed to a document released in April by the Afghan Independent Human Rights Commission (AIHRC) that says 398 prisoners were abused, mostly in 2006 and 2007.

Canada is not mentioned by name in the report, and it's unclear which NATO partners would have transferred the prisoners.

"How can the minister be so sure that absolutely none of them are relevant to the Canadian situation?" Layton said, referring to a warden at an Afghan prison who stated that prisoners were beaten with cables, their hands and legs tied.

Defence Minister Peter MacKay replied that Layton just assumed some of the prisoners may have been transferred by Canadians.

"That is the crux of the issue. We are asking for these allegations to be proven. There have been no proven allegations that we can refer to," MacKay said.

MacKay said the report is broad, and doesn't "apply to the numbers that were transferred" by Canadians.

"We stopped transferring when the agreement wasn't working," MacKay said, adding that the government has invested its resources in improving the transfer process.

Liberal Leader Michael Ignatieff asked why the government halted prisoner transfers more than once, and whether the torture allegations were the cause. 

"Can't the government tell us the truth on this issue?" he asked.

Prime Minister Stephen Harper was not in the House to answer questions -- instead, he was at a photo opportunity with Canada's national men's lacrosse team.

Allegations of abuse resurfaced last week after Richard Colvin, a former senior diplomat in Afghanistan, said he told the government in writing that prisoners were likely tortured in 2006-2007 -- including many innocent people -- but officials told him to stop filing reports.

The government has brushed off his comments as not credible, despite the fact that he was the second-highest official in Afghanistan at the time, and continues to be employed by the government in Washington.

In the House, Liberal defence critic Ujjal Dosanjh said the accusations are a black eye on Canada, which has a reputation as a promoter of human rights.

"The actions of the Conservative government undermine our reputation abroad. They also undermine the work of our brave men and women in uniform," he said.

The New Democrats and Liberals continued to call for a public inquiry into the matter. Layton demanded MacKay table evidence that shows exactly what happened to prove Canada was not involved.

"I assume now then we'll get all the evidence about the visits that took place in those particular cases so we can see exactly what happened," Layton said. "Will the minister table them in this House?"

MacKay said the government made three decisions to stop transfers to the Afghans this year because the Afghan officials were "not living up to expectations." He explained the Afghans were not allowing Canada unannounced access to prisons so the transfers stopped until they were let in.

He said the government acted as soon it learned of "credible allegations."

In response to Colvin's accusations, a senior advisor on Afghanistan said he encouraged diplomatic officials to report their observations "freely and honestly" and meet the "highest standards of accuracy."

David Mulroney wrote a letter to the parliamentary committee investigating allegations of prisoner abuse, saying that Canada is at the forefront of detainee monitoring and knew that "the human rights situation in Afghanistan was cause for concern."

Mulroney, who is now Canada's ambassador to China, said he backs the work of Canadian civilian and military officials "to put in place a very robust system to assist Afghanistan in meeting its ... commitments for the humane treatment of detainees."