Canada's troubled foreign minister has resigned after it emerged today that he left secret documents at his then girlfriend's house.

Canada's troubled foreign minister has resigned after it emerged today that he left secret documents at his then girlfriend's house.

Prime Minister Stephen Harper said today that he had accepted the resignation of Maxime Bernier, who came under fire in recent weeks after it was reported that his ex-girlfriend Julie Couillard had previous relationships with Hells Angels motorcycle gang members and links to organised crime.

"Mr Bernier has informed me that he left classified documents in a non-secure location. This is a serious error," Mr Harper said.

The documents were left at a private residence in the spring, Mr Harper said. He did not say what the documents were.

But he insisted Mr Bernier's relationship with former model Ms Couillard was not a factor in the decision.

"It's only this error. It's a very serious mistake for any minister. We must always accept responsibilities for the documents that are classified," Mr Harper said. "The minister has immediately acknowledged the gravity of this mistake."

But the resignation came as Ms Couillard prepared to appear on a French-language television station to say that her former lover was careless with classified documents.

Ms Couillard would not comment on the nature of the document except to say that Mr Bernier left it behind at her place.

She said she contacted a lawyer for advice, who told her it was the property of the Canadian government.

"The document was given back," she said.