Prime Minister Justin Trudeau will be returning to Ottawa without the majority government mandate Liberals had hoped for when he called the early election last month.

Early Tuesday, the Liberals were hovering between 155 and 157 seats. The former is the number they had when Trudeau called the election in August, and the latter is what they won in 2019.

The Conservatives were teetering on 121 or 122 seats, after winning 121 less than two years ago.

They will remain the official Opposition, with leader Erin O'Toole promising the "changed" party he leads will speak for all Canadians from all walks of life.

The Bloc Québécois and NDP will bring up the rear, each individually potentially holding the balance of power in the minority House of Commons, both also within a few seats of their 2019 tallies.

With more people voting by mail than ever before, the final result in some ridings might not be known for days.

Elections Canada will start counting more than 780,000 mailed-in ballots Tuesday, and it expects most to be finished by Wednesday, but officials did warn some ridings could take up to four days for final counts.