Fewer than half a dozen members of the military — most of them with the air force — are part of exchange programs with British, Australian and U.S. forces, all of which are still+ engaged in anti-Taliban operations in Kandahar.
New Democrat defence critic Jack Harris accused MacKay of misleading the House of Commons and the public, which expected no Canadians would be in harm's way after Canada withdrew from southern Afghanistan last year.
Harris also said the exchange program violates the motion passed by the Commons in 2008, which ordered an end to Canadian combat operations by the end of 2011.
MacKay denied the exchange program contravened the motion and says the participation is part of the country's broader policy of co-operating with allies.
"This is very much about Canada continuing its long-standing commitment to work with our allies in Afghanistan and around the world," he said.
As Canadian troops made their exit from Kandahar, the Harper government formulated a strict policy to conform with the wishes of Parliament, but in the spring of 2011, National Defence quietly petitioned for an exemption because several soldiers were slated to serve with the U.S Army.
Documents and briefings obtained by The Canadian Press under access to information laws show that since the exemption, four Canadian soldiers have fought in Kandahar under the flags of other nations.
But the government made a commitment that no Canadian would be involved in combat, Harris said.
"Why can't we trust the minister and the prime minister at their word? And why won't Conservatives respect the motion passed by this House of Commons?" he said during question period.
The last time the program came under scrutiny was during the U.S.-led war in Iraq, which the Chretien government refused to join. It did, however, quietly allow several senior officers to serve with American forces in staff positions.
That list includes the country's top soldier, Gen. Walt Natynczyk, who is about to retire.
However, an email note from National Defence indicates that the government did exercise its option to hold back some soldiers on secondment from participating in combat operations in Iraq.
Canadian Forces "personnel have not been prevented from receiving training and experience in exchange positions," spokeswoman Lauri Sullivan wrote.
"With the exception of Iraq, CF members have served on exchange with numerous host nations around the world in recent years."
Indeed, the briefing material indicates that last year, Canada's deputy top military commander considered ordering three soldiers seconded to the U.S. in Afghanistan to stay back if the government didn't approve the exemption.
The March 22, 2011 briefing note to the head of the Canadian Army noted that approving the deployment of one soldier without the new policy in place would run the risk that "he would have to be repatriated mid-tour should it be rejected."
Harris said the government and the military clearly has the option to hold soldiers back if it chooses to do so.