Canadian Prime Minister Mark Carney's Liberals could soon have a slim majority in the House of Commons if the party is able to make gains in three by-elections being held on Monday.

The outcome of the races - two in the Toronto area and one near Montreal - could solidify his hold on power, staving off a federal election until as late as 2029 and giving his party the ability to pass legislation without relying on support from opposition benches.

Liberals currently hold 171 of the 343 seats in the House, one shy of a technical majority.

The likely power shift comes a year after Carney became prime minister and follows a series of defections by opposition members of parliament to the Liberals.

The Liberals are widely expected to win the two Toronto ridings, or constituencies, of Scarborough Southwest and University-Rosedale. These seats were previously held by former defence minister Bill Blair and Chrystia Freeland, who served as deputy prime minister under Justin Trudeau.

The race in Terrebonne, a Montreal suburb, is considered a toss-up between the Liberals and the Bloc Quebecois. The Liberal candidate won by a single vote in last year's federal election, which was later nullified by Canada's top court due to a clerical error regarding a postal ballot.

Wins in Toronto will be enough for Carney to clinch a narrow majority, bolstered by recent party-switches from five defectors, including four former Conservatives and one member of the left-wing New Democratic Party.

Political experts have commented on the extraordinary rate of defections, noting that Carney's broader appeal may lead to less ideological coherence within the party.

Polling suggests the Liberals are performing well, averaging about 10 to 15 points ahead of the Conservative Party, with Carney enjoying significant support from the public.

Under Carney's leadership, the Liberals have shifted towards more conservative policies, appealing to right-of-centre MPs. This change includes ending certain signature initiatives from the previous Trudeau administration.

As the by-elections approach, tensions remain high between the parties, with the Conservatives accusing the Liberals of backdoor deals to gain power. This atmosphere sets the stage for significant political developments that could shape Canada's future governance.