President-elect Donald Trump's threat to impose tariffs on Canada, China and Mexico on the first day of his administration could dramatically raise prices for Americans on everything from cars to clothes to oil.

President-elect Donald Trump took to social media to announce that one of his first executive orders will be a 25 per cent tariff on all products entering the U.S. from Canada and Mexico.

The president-elect calls it an effort to force them to crack down on illegal immigration and drug smuggling into the US.