Prime Minister Justin Trudeau said his government is prepared to work with the U.S. to ensure that Canada doesn’t become a conduit for cheaper steel imports from other countries.

Mr. Trudeau added Tuesday that Canada has strengthened efforts to protect its steel industry over the past two years and can use tariffs and countervailing duties to keep unfairly produced products out of the market. He said he is aware of concerns that steel could be shipped into Canada, which is exempt from U.S. tariffs, as a way to get it into...