TORONTO (Reuters) - Ottawa and the provinces will respond robustly if the incoming U.S. administration goes ahead with a promise to impose tariffs on imports from Canada, Finance Minister Chrystia Freeland said on Friday.

Prime Minister Justin Trudeau, Freeland and the 10 provincial premiers have held two phone calls recently to discuss how best to react if President-elect Donald Trump slaps a 25% tariff on U.S. imports from Canada.

"In the event that the United States were to impose unjustified tariffs on Canada, of course we would respond, and the Canadian response would necessarily be robust. I am confident that it would be effective," Freeland told reporters.

Trump has said he will keep the tariffs in place until Canada clamps down on drugs and migrants crossing the border.

Bloomberg reported on Thursday that Canada was examining the possible use of export taxes on commodities including uranium, oil and potash.

A Canadian government source said while all options for retaliation were on the table, ministers and officials were nowhere near taking any kind of decision.

Although Freeland said Ottawa and the provinces would need to present a united front, some provincial premiers are unhappy about the proposed response.

Scott Moe, premier of the western province of Saskatchewan, said export taxes "would be a complete betrayal" by the Trudeau government. Saskatchewan produces oil, uranium and potash, he noted.

"Export taxes on these commodities would be a self-destructive response to U.S. tariffs as they would only increase the harm to our economy and jobs," he said in a post on the X social media network.

Alberta Premier Danielle Smith said her oil-producing province would "not support cutting off our Alberta energy exports to the U.S., nor will we support a tariff war with our largest trading partner and closest ally".

(Additional reporting by David Ljunggren in Ottawa and Ryan Jones in Toronto; Editing by Rod Nickel)