The mayors of Canada's big cities are taking a cautious approach to the inauguration of the new American president.

They met in Ottawa on Friday to discuss municipal-federal co-operation with Prime Minister Justin Trudeau, but could not avoid discussing Donald Trump.

Of particular concern is Trump's inflammatory statements about ripping up the North American Free Trade Agreement and the effect that would have on Canada's economy and countless citizens.

In recent weeks Trudeau has reminded Trump of the historically close ties between the two countries.

But Montreal Mayor Denis Coderre said cities will have a voice, and the power to moderate negative effects.

"We're working with the government in place but I know one thing, there's a new counterbalance called cities," said Coderre.

"There are some issues and trade issues, water issues, and I think that... Listen we have to give him a chance. Of course we're not in agreement with everything he's saying."

Several mayors said they were hopeful that Trump's attitudes toward Canada, and his priorities, would change for the better now that he is in office.