U.S. President Donald Trump is promising to tax steel imports again less than a week after Prime Minister Justin Trudeau said he believed Canada will escape expected steel tariffs imposed by the U.S.

Speaking to reporters as he flew to France for a bilateral meeting, Trump said there are two ways to address what he calls unacceptable dumping of foreign steel into the U.S. market — quotas and tariffs.

"Maybe I'll do both," he said according to a transcript of the conversation released by the White House Thursday.

"Steel is a big problem. Steel is, I mean, they're dumping steel. Not only China, but others. We're like a dumping ground, okay? They're dumping steel and destroying our steel industry, they've been doing it for decades, and I'm stopping it. It'll stop."

The comments came immediately after Trump spoke about the trade deficit the U.S. has with South Korea, which is the third-largest source of steel imports to the U.S.

But Canada is the biggest, accounting for 17 per cent of all steel imported into the United States last year.

Steel was one of the subjects discussed by Prime Minister Justin Trudeau with Trump on the sidelines of the G20 leaders' summit in Germany last weekend. Trudeau told reporters after he was "comfortable" Canada would not be affected by any national security-related import tariffs on steel.

"The kind of back and forth complimentarity between Canada and the U.S. on steel is something we both value tremendously as countries and will ensure to protect," Trudeau said July 8.

The U.S. Department of Commerce is weeks overdue in deciding whether or not to slap new import duties on steel on the basis of national security. Commerce Secretary Wilbur Ross was to have made the decision in June but as of Thursday, nothing had been finalized.

He was briefing congressional representatives on the issue in Washington Thursday.

Steel is also set to be on the agenda Friday when Trudeau has a bilateral meeting with U.S. Vice President Mike Pence during the annual meeting of the National Governor's Association in Rhode Island. Softwood lumber and NAFTA are also set to be discussed. Negotiations on the trade deal will begin mid-August, while Canada and the U.S. are currently negotiating a new trade deal on softwood lumber.

Foreign Affairs Minister Chrystia Freeland will also be at the meeting.

Her spokesman said Thursday Canada's feelings on steel remain the same as they were following the G20.

"Our North American steel and aluminum industries support good middle class jobs, are highly integrated, and our trade is highly balanced," said Adam Austen. "As key allies and partners in Norad and NATO, Canada and the U.S. are integral to each other's national security and Canada is a safe and secure supplier of steel and aluminum to the U.S."

Amanda DeBusk, chair of the international trade department at the D.C. law firm Hughes Hubbard and Reed, said while the Trump administration's international trade policies may be less predictable than his predecessors, there is reason for Canada to be optimistic.

"If you look at the history of trade relations in the past the U.S. has given Canada and Mexico a pass on the types of trade restrictions that are being talked about in regards to steel," she said.

The U.S. steel industry fight with China and other countries predates Trump. At the end of 2016, before Trump was inaugurated, the U.S. already had 113 different trade remedies in place on steel imports including 20 against China alone. None of them were against Canada.