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Prime Minister Mark Carney at the Canadian embassy in Tokyo on March 7. He announced the three byelections in a statement on Sunday.Adrian Wyld/The Canadian Press

Three federal by-elections will take place April 13, Prime Minister Mark Carney announced Sunday.

The by-elections aim to fill vacancies in the Ontario ridings of Scarborough Southwest and University-Rosedale, as well as one in the Quebec riding of Terrebonne, near Montreal.

A Liberal sweep of all three ridings would bring the party’s seat count in the House of Commons to 172, which is technically the minimum threshold for a majority government.

However, the current Speaker is a Liberal MP and the Speaker only votes in the event of a tie. Convention dictates that when the Speaker votes, they should side with preserving the status quo, meaning that even at 172 seats, the Liberals would still need co-operation from at least one opposition MP in many cases.

In the federal election last April, Liberal Tatiana Auguste defeated Bloc Québécois candidate Nathalie Sinclair-Desgagné by the narrowest of margins in the riding of Terrebonne.

After the election, a voter in the riding said she had cast her ballot for the Bloc by mail but that her ballot was returned to her because of an error in the postal code of the polling station.

Last month, the Supreme Court annulled the one-vote Liberal victory.

Ms. Sinclair-Desgagné has said she will run again for the Bloc in the byelection.

Scarborough Southwest became vacant after Mr. Carney appointed veteran Liberal MP and former cabinet minister Bill Blair to be Canada’s next high commissioner to the United Kingdom.

Doly Begum, the former deputy leader of the Ontario New Democrats, will run for the federal Liberals in the by-election in that riding.

Liberal MP Nate Erskine-Smith, who is planning to run for the leadership of the Ontario Liberals, has said he would seek the provincial nomination in the same riding, which would create a vacancy in his current federal riding of Beaches-East York.

University-Rosedale was previously held by former deputy prime minister and Liberal MP Chrystia Freeland. She is now a volunteer adviser to Ukrainian President Volodymyr Zelensky, chief executive officer of the Rhodes Trust and a media contributor to Bloomberg News.

Family doctor and health care advocate Danielle Martin is the Liberal candidate in that riding. Serena Purdy, who finished third in last year’s federal election, recently announced she will run again as the NDP candidate.

The Conservative Party has not announced a candidate in any of the three ridings.