US President-elect Donald Trump said Wednesday it would be "a great idea" for Canada to become the 51st US state, teasing on social media that "many Canadians" welcome the idea, as Ottawa is wracked by political turmoil.

"Many Canadians want Canada to become the 51st State," Trump posted on Truth Social.

"They would save massively on taxes and military protection. I think it is a great idea. 51st State!!!" he added.

The post is not the first time Trump has publicly mused at the idea, a joke that some have found in bad taste, particularly following the shock resignation of Canada's deputy prime minister on Monday.

A Leger public opinion survey this week found 13 percent of Canadians support the notion of linking up with their southern neighbor.

When Trump made the same comment to Canadian Prime Minister Justin Trudeau at a dinner at his Mar-a-Lago estate in Florida in late November, howls of laughter reportedly erupted.

According to Fox News, Trump suggested that merging the two nations would not only resolve his concerns about fentanyl trafficking, over which he has threatened a 25-percent tariff on Canadian goods but could also stem illegal immigration -- an issue that mainly affects the US southern border.

His suggestion raised eyebrows in Ottawa with some commenting that it was "not funny," humiliating and a not-so-subtle threat on the part of the incoming US leader.

Since then, Trump has repeatedly referred to Trudeau in social media posts as the governor of Canada -- a title used by leaders of the 50 US states.

The jabs may have become more worrying for Canadians since the resignation of Deputy Prime Minister Chrystia Freeland this week, which spurred calls for Trudeau to quit.

- 'Boxer working a cut' -

Former Trudeau advisor Gerald Butts reacted on social media: "Trump is like a boxer working a cut."

Norman Spector, an ex-staffer to former Canadian prime minister and Trump golfing buddy Brian Mulroney, wondered if Trump seriously wanted to annex the United States' northern neighbor.

"That will never happen," University of British Columbia politics professor Max Cameron told AFP.

"Nothing could be a greater impediment to Canada more closely integrating with the United States than Donald Trump in office in Washington," he added.

"I suspect this is all part of a pattern of bullying that is how he approaches negotiations."

Queen's University professor Stephanie Chouinard echoed that view, saying Trump "is taking advantage of the chaos in Canadian politics this week to further antagonize Trudeau."

Public Safety Minister Dominic LeBlanc has insisted that despite Trump's teasing, he and Trudeau have had "productive" discussions with the president-elect and his team.

On Tuesday, LeBlanc and Immigration Minister Marc Miller announced border security and immigration measures aimed at placating Trump, including hiring hundreds of new police and border officers, and aligning Canada's asylum system with the United States' to quickly weed out claims that do not meet requirements.

Ottawa has also proposed setting up a joint Canada-US "strike force" to combat transnational crime groups, and beef up its military spending.

Trump in his post also said the United States was subsidizing Canada "to the tune of over $1,000,000,000 a year. Makes no sense!"

It was unclear what Trump's figure was referring to.

According to US data for 2022, the trade deficit with Canada was $53.5 billion. Most economists dismiss this as insignificant when compared to the $909 billion worth of goods and services traded by the two countries.

Julien Martin, an economics professor at the University of Quebec in Montreal, explained that for Republicans under Trump, "trade deficits are a big problem for the American economy."

They represent "job losses and the decline of the manufacturing sector," he said.