TORONTO -- With about 1 million voters sending in their 2021 ballots by mail, Canadians may have to wait longer than usual to find out who will form the next government.

According to the latest data from Elections Canada, nearly 1.3 million mail-in ballots were sent to voters this year, and 951,039 had been returned as of Monday morning. However, that number was expected to rise as mail-in ballots could be returned up to the moment polls closed.

With the 2021 election coming amid the continuing COVID-19 pandemic, Elections Canada prepared for as many as 2 million to 3 million mail-in votes. While the final number of mail-in ballots requested is considerably less than that, it is orders of magnitude above the 50,000 mail-in votes cast in 2019.

The make-up of the mail-in ballots also shows the impact of the pandemic, as roughly 80 per cent of the mail-in ballots requested -- 782,310 at last count -- are from voters casting ballots from within their ridings, as opposed to voters outside of their ridings or overseas voters.

However, even with extensive preparation, the mail-in ballots promise to extend the normal timeline for ballot counting.

That’s because mail-in ballots cast from within a voter’s riding are subject to an ‘integrity check,’ which verifies that the outer envelope has been signed and that the voter has not also voted in person, among other measures. Because of the need for this verification, the counting of those votes will not begin until Tuesday at the earliest.

Such checks are not needed for voters casting votes from other countries, or from incarcerated voters or members of the military, as there is no need to verify whether or not those voters also cast ballots in person. As such, their ballots can be counted ahead of the polls closing on Monday.

An Elections Canada spokesperson told last week that the counting process for mail-in ballots could take between two to five days to conclude.

This could delay results in close ridings. It could also delay a clear picture on who will form the next government, although that result is typically called well before vote counting has concluded.