The new U.S. ambassador to Canada says Washington believes the North American Free Trade Agreement is working well.

David Jacobson told a crowd of business leaders in Montreal on Wednesday that the United States has no immediate plans to reopen NAFTA.

"There may be, with respect to labour and the environment, side letters that may improve the situation from the perspective of all three countries," he said. "But fundamentally our view of NAFTA is that it is working very well. It is working very well for all sides."

In the last U.S. presidential election campaign, then candidate Barack Obama talked about reopening the trade deal, which prompted some unease in the Canadian business community about a return to protectionism. Critics of the pact also say it does little to enhance environmental and worker protections in Canada, the U.S. and Mexico.

Jacobson said talks are underway to resolve Canada's concerns over protectionist Buy American policies. NAFTA generally prohibits its member countries from favouring domestic companies for most high-value government procurement.

Stockwell Day, Canada's minister of international trade, will also speak at the business leaders' meeting.

With files from The Canadian Press