TORONTO - Canada will work swiftly to sell U.S. president-elect Barack Obama on the importance of the countries' trade relationship and lobby against any protectionist anti-NAFTA talk, ambassador to the United States Michael Wilson said Monday.

The North American Free Trade Agreement was frequently attacked during the Democratic primaries for costing Americans jobs and Wilson said that promoting an even stronger trade relationship with the U.S. will be a priority for Canada.

"We must continue to work together to deepen and strengthen this trading relationship that's been so beneficial for both of our countries," Wilson said during a speech to the Canadian Club of Toronto.

"We'll impress that view on the new administration and particularly on Congress, where protectionist measures are more likely to be felt."

Wilson found himself embroiled in the so-called NAFTA-gate scandal in February. Both Obama's and Hillary Clinton's campaigns were alleged to have assured Canadian officials that they had no real intentions of re-opening NAFTA, despite what they said on the campaign trail.

The prime minister's former chief of staff, Ian Brodie, suggested to reporters that Clinton's camp told Canadian officials that NAFTA was safe, and a subsequent report said Wilson had been told the same by Obama's inner circle.

A leaked document written by a Canadian diplomat chronicled a conversation between one of Obama's economic advisers and diplomats at Canada's Chicago consulate and appeared to support the story.

Wilson and Obama denied the report but the leak was credited with helping Clinton win the Ohio primary.

An investigation into the source of the leak cleared both Wilson and Brodie - who later stepped down.

Wilson did not address the controversy in his speech Monday and refused to take questions from journalists.

In Ottawa, Liberal Leader Michael Ignatieff said the leak was an embarrassing episode for Canada and Prime Minister Stephen Harper may have to work to repair his relationship with Obama in their first official meeting.

"The incompetent or malicious intervention in the Ohio primary will not be soon forgotten by people inside Obama's regime," Ignatieff said.

Wilson also said Canadian embassy staff in Washington are now tasked with trying to assess what directions the Obama administration will focus on first, and noted it's already clear environmental issues will be near the forefront.

He said one of Canada's biggest challenges with the administration may be in defending its environmental record.

"We supply an increasing share of U.S. energy, more than any other foreign country, yet we are increasingly seen as foreign in an adverse sense and purveyors of dirty oil," he said.

"This image is fed in part by some negative perceptions of the Canadian oilsands industry."

Wilson is a former Conservative MP and was finance minister under Brian Mulroney when the GST was introduced. He was also a minister of state for international trade and was a negotiator in developing NAFTA.