March 6 (Bloomberg) -- Canadian opposition parties demanded Prime Minister Stephen Harper fire his chief of staff following media reports that he described a campaign aide to Hillary Clinton as saying her position on the North American Free Trade Agreement can be taken with a ``grain of salt.''

Canadian Press, citing an unidentified source, reported yesterday that Chief of Staff Ian Brodie made the remark on Feb. 26. Clinton spokesman Phil Singer said the campaign ``did not sanction nor would we ever sanction anyone to say such a thing.'' Singer said the Canadian government was free ``to reveal the name of anyone they think they've heard from.''

Previously, a memo was leaked that attributed similar comments to an adviser for Illinois Senator Barack Obama, New York Senator Clinton's opponent in the Democratic primary campaign. Harper said March 4 that Brodie wasn't the source of the memo and that the leak was being investigated by the head of the country's public service.

``The least the prime minister can do is relieve him of his duties until the investigation is complete,'' Navdeep Singh Bains, the opposition Liberal Party lawmaker responsible for international trade, said by telephone. ``Ideally we want him to resign.''

Jack Layton, leader of the opposition New Democratic Party, also has called for Brodie's resignation. Asked today in Parliament whether the allegations against Brodie would be part of the probe, Harper promised a ``thorough investigation.''

``We will investigate this entire matter,'' Harper told lawmakers.

`Political Positioning'

The leaked memo described a meeting last month between Austan Goolsbee, Obama's top economic adviser, and Canadian consulate officials in Chicago. The memo said Goolsbee assured them that Obama's promise to re-open Nafta to negotiation was ``more about political positioning than a clear articulation of policy plans.''

That leak came ahead of Clinton's victory in the March 4 Ohio primary, where job losses were a major election issue. During the final days of the campaign in that state, Clinton accused Obama of misleading voters about his views on trade.

Harper said the memo's circulation was ``unacceptable'', and was ``blatantly unfair'' to the Obama campaign.

David Wilkins, U.S. ambassador to Canada, said in an interview to be broadcast tomorrow on CBC Radio that the leaked memo was an act of ``interference,'' while saying he didn't think it was intentional, according to CBC's Web site.

`Not to Worry'

Canadian Press said yesterday that Brodie may have triggered the scandal by telling reporters that a Clinton campaign official told Canadian embassy staff ``not to worry'' about her calls to renegotiate the trade agreement. A day after Brodie is alleged to have made the comment, Canada's CTV television network said aides to Clinton and Obama may have contacted Canadian officials to play down their comments about Nafta. Clinton's campaign denied the story at the time.

The prime minister's office directed media calls for Brodie to the press office, and Director of Communications Sandra Buckler didn't return telephone calls seeking comment.

Canadian opposition parties are accusing Harper's Conservatives of leaking the information to help the Republican Party in the U.S. presidential elections.

To contact the reporter on this story: Theophilos Argitis in Ottawa at targitis@bloomberg.net.

Last Updated: March 6, 2008 17:23 EST