Elections Canada has announced the dates for two federal byelections to be held in Quebec and Alberta ridings vacated by Conservative MPs.

The votes in Sturgeon River-Parkland, Alta., and Lac-Saint-Jean, Que., will be held on Monday, Oct. 23.

Conservative interim leader Rona Ambrose had previously held the seat in Sturgeon River-Parkland, just west of Edmonton.

Ambrose resigned from politics in July after serving as party leader since 2015.

The Quebec seat was previously held by Denis Lebel, who announced his retirement in June after nearly 10 years in the House of Commons.

The byelections could be an early test for new Conservative Leader Andrew Scheer, particularly in Lac-Saint-Jean, where Lebel won in 2015 with only 33 per cent of the vote.

Voters in the two electoral districts can cast their ballots in person or by mail.