Prime Minister Stephen Harper downplayed revelations of a "contingency plan" to deal with accusations that prisoners handed over to Afghan authorities were tortured.

As first reported by CBC News on Monday, Canadian officials started drafting a plan on how to deal with accusations that prisoners in Afghan custody were being tortured as early as March 2007 — months before allegations of prisoner abuse at the hands of Afghan authorities first appeared in the media.

During Tuesday's question period, Harper said details about contingency plans had been "thoroughly aired" months ago, and said the plan ultimately led to a "new and enhanced" transfer agreement with Afghanistan in 2007.

NDP Leader Jack Layton asked the prime minister to provide details about when Ottawa learned about the torture allegations, and blasted the government for preparing what he called a "spin document" instead of stopping the transfer of prisoners.

Harper defended the government's actions, saying allegations from the opposition were baseless.

"Truth of the matter is, of course, that Canadian diplomats, Canadian military personnel have at all times respected Canada's international obligations," Harper said.

Liberal Leader Michael Ignatieff renewed his call for a full public inquiry into the treatment of Afghan detainees, saying the government no longer has any credibility on the issue.

“They’re caught in a scandal of their own making because they won’t tell Canadians the truth,” Ignatieff said.

Harper dismissed calls for a public inquiry and defended the government’s decision to appoint retired Supreme Court justice Frank Iacobucci to review Afghan detainee documents, saying Iacobucci will have access to “all relevant documents” relating to the treatment of Afghan detainees.

Ignatieff argued that the former judge doesn't have a strong enough mandate, and he pushed the government to give Iacobucci the power to preside over a full public inquiry.