Canadian prime minister Justin Trudeau is fighting for his political life, amid a plunge in popularity and the threat of vote of no-confidence.

In an indication of the challenges confronting the 52-year-old premier, Mr Trudeau’s Liberal Party has its back against the wall in a by-election in the federal riding of LaSalle-Émard-Verdun in Quebec.

Normally, the Liberals would have expected to win Monday’s contest, but polls showed its candidate being pressed hard by that of the Bloc Québécois.

Meanwhile, conservatives in parliament are threatening to call a vote of no confidence later this week against Mr Trudeau, who has been heading a minority administration since the 2021 election.

The Liberals have been depending on a supply-and-confidence agreement with the New Democratic Party (NDP). But last week, the NDP ended the arrangement, that had acted as a lifeline for Mr Trudeau.

Canadian Conservative leader Pierre Poilievre has called on his counterpart in the NDP, Jagmeet Singh, to support the no-confidence motion and trigger an election.

“Will Jagmeet Singh sell out Canadians again?”Mr Poilievre said at a news conference in Ottawa. “It’s put up or shut up time for the NDP.”

Mr Singh responded by saying he will not be pressured.

“I’ve said on any vote we will look at the vote and we’ll make our decision,” Mr Singh said at a party meeting in Montreal. “We’ll make a determination of what is in the best interests of Canadians. Unlike Pierre Poilievre who wants to play games, we actually want to get things done for Canadians.”

Voters are angry, Trudeau admits

Mr Trudeau, who still insists he will lead the party into an election that must be held by the end of October 2025, suggested voters in Monday’s by-election would be drawn to vote by anger over elevated prices and a housing crisis.

“Canadians right now are facing difficulties with the high cost of living. They are very frustrated,” he said last week.

Mr Trudeau, in his ninth year as prime minister, has seen his approval rating plummet from 63 per cent when he was first elected in 2008, to 28 per cent in June of this year.

His popularity has sagged as voters struggle with a surge in the cost of living and a housing crisis that has been fuelled in part by an increase in arrivals of temporary residents such as foreign students and workers.

This has caused serious problems for the Liberal Party. In one recent by-election, its candidate lost a seat the party had held for 30 years.

Polls suggest that the Liberals will lose badly to the Conservatives in the the next federal election. A Leger poll last week put the Conservatives on 45 per cent, a level of broad support rarely seen in Canada, with the Liberals in second place on 25 per cent.

If the Liberals lose in LaSalle-Émard-Verdun, it is likely blame will fall once again on Mr Trudeau.

Some Liberal politicians are even are breaking ranks with a call for change at the top. Alexandra Mendes, a Liberal legislator who represents a Quebec constituency, said many of her constituents wanted Trudeau to go.

“I didn’t hear it from two, three people - I heard it from dozens and dozens of people,” she told public broadcaster Radio-Canada last week. “He’s no longer the right leader.”