Former chief of defence staff Rick Hillier says he's never heard suggestions that Canada may have been complicit in the torture of detainees in Afghanistan. (Les Perreaux/Canadian Press)

Former chief of defence staff Rick Hillier said Thursday he never heard suggestions that Canada may have been complicit in the torture of detainees in Afghanistan.

Speaking in Toronto at a public event to promote the release of his memoir, A Soldier First, Hillier said there was "no smoking gun that has ever caught my attention."

Earlier this week, Canadian diplomat Richard Colvin raised those allegations when he testified before a parliamentary committee. Colvin said he repeatedly tried to get the attention of officials, bureaucrats, even the Prime Minister's Office.

Colvin alleged that prisoners were turned over to Afghanistan's notorious intelligence service by the Canadian military in 2006-07 despite warnings that they would be tortured. He also suggested the federal government may have tried to cover up what was happening.

"The guy said some things and, really, nothing ever caught my attention based on what he perceived he said or perceived he sent," Hillier said Thursday. "

The opposition parties attacked the government over Colvin's allegations, and demanded a public inquiry. The government has rejected that call.

In the House of Commons on Thursday, Defence Minister Peter MacKay defended the government.

"There has not been a single, solitary proven allegation of abuse involving a transferred Taliban prisoner by Canadian Forces," MacKay said.