US President Donald Trump says that trade negotiations are "complicated", but that Canada will be "very happy" with any deal in the future.

Speaking alongside Canadian Prime Minister Mark Carney during a cordial meeting at the White House, Trump said that car companies "hurt" the US by setting up operations across the border, placing the two neighbours "in competition".

Carney said he was confident they would "get the right deal" from the US, Canada's primary economic partner.

Canada's main opposition figure, Conservative opposition leader Pierre Poilievre, had said anything short of a deal would mean the visit was a failure.

During Tuesday's White House visit - Carney's second since taking office in March - both men seemed optimistic about the prospects of eventually reaching an agreement, even if Trump said that doing so would be a complex proposition.

The US president has imposed a 35% levy on Canadian imports, although he has allowed exemptions for goods that fall under the USMCA - a free trade agreement with Mexico and Canada that Trump negotiated during his first term.

Trump has also imposed sector-specific levies on Canadian goods, including 50% on metals and 25% on automobiles.

The US president told reporters that the relationship between the two neighbours was one of "natural conflict".

"We also have mutual love," he said. "We have great love for each other. I love Canada and the people of Canada."

Trade negotiations between the two countries have dragged on past an August deadline, and Canada remains the only G7 country not to have reached a trade deal with Trump this year.

Illustrating why the two countries have a "complicated" economic relationship, Trump cited the car industry.

"The problem is that they want a car company, and I want a car company," he said. "They want steel, and we want steel... in other countries, they're very far away and there's no problem."

"We don't like to compete because we sort of hurt each other," Trump added. "It's a natural business conflict. Nothing wrong with it. I think we've come a long way over the last few months."

Carney repeatedly praised Trump and emphasised the scale of Canadian economic and investment ties in the US, where it sells 75% of its goods.

"There are areas where we compete and it's in those areas we have to come to an agreement that works," Carney said.

"But there are more areas where we are stronger together, and that's what we're focused on. We're going to get the right deal."

While Trump has recently revived talk of Canada becoming the 51st state of the US, the topic was mentioned only briefly on Tuesday, with both leaders laughing when it came up.

Carney told Trump on his last Oval Office visit back in May that Canada "won't be for sale... ever".

Tuesday's meeting ended on a friendly note, with Trump referring to Carney as a "very strong" leader and a "tough negotiator".

Asked what was holding up any agreement, Trump responded without hesitation.

"I want to be a great man, too," he said.

Their warm tone was a striking departure from Trump's combative relationship with the last Canadian Prime Minster, Justin Trudeau.