Ontario voters in three ridings are set to head to the polls Sept. 3, as Premier Doug Ford called byelections today.

Scarborough Southwest has been vacant since February when Doly Begum, who held the riding provincially for the NDP, resigned to successfully run for the federal Liberals there.

In the months after her resignation, the riding became somewhat of a flashpoint after former MP Nate Erskine-Smith failed to win the Ontario Liberal nomination and made accusations of impropriety in the race, which the party said were unsubstantiated.

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A byelection will also be held in York-Simcoe, which was vacated in June with the resignation of Caroline Mulroney, who served in cabinet as president of the Treasury Board.

The resignation of another cabinet minister, Minister of Sport Neil Lumsden, has triggered a byelection in Hamilton East-Stoney Creek as well.

Ford will also have to fill the cabinet posts of Mulroney and Lumsden, as well as Stan Cho, who resigned last month as minister of tourism, culture and gaming amid an expense scandal, though he remains in the Progressive Conservative caucus.