TORONTO -- When Canadians head to the polls on Sept. 20, they’ll be casting a ballot in what is expected to be the most expensive federal election campaign to date.

The estimated cost of the 44th federal election is $610 million, about $108 million more than the $502.4-million price tag for the 2019 election.

Why is it so expensive? Blame it on COVID-19 and a growing population.

“The main thing is COVID-19,” Lars Osberg, an economics professor at Dalhousie University, told CTV’s Your Morning on Wednesday. “When you have an election in COVID times, you have to have more people around the polls, you have to have Plexiglas everywhere, you have to have all the COVID protocols.”

And that simply adds up.

About $50 million of the new expenses this year will go to pandemic protocols and another $50 million will be due to population growth, Elections Canada said. There are about 38.1 million people living in the country now, compared with about 37.4 million in 2019.

“The last election cost Canadians about $18.35 per registered voter,” Osberg said. “And the population has increased, so it’s kind of normal that the expenses of an election increase.”

The bulk of the election costs in the last federal vote -- $438 million -- went toward preparing for and running the actual event. It covered recruiting and training more than 200,000 election workers, printing ballots and lists of electors, leasing local offices and about 18,000 polling places, communications campaigns, IT equipment and shipping election materials. In 2019, all of this accounted for 87.25 per cent of the total election cost.

The remaining $64.4 million went toward reimbursing parties and candidates. To be eligible for partial reimbursement of election expenses, candidates must be elected or obtain at least 10 per cent of the valid votes cast in their electoral district.

“There are a lot of fine details that go into running an election,” Osberg said.

And holding an election during the pandemic means accommodating for the times.

Although the 250,000 polling workers won’t be required to be fully vaccinated, the polling stations will be “highly controlled,” Chief Electoral Officer Stephane Perrault said in a press conference on Aug. 18.

“[Canadians] can expect to see essentially the kind of measures that they now have been seeing for the last 18 months. So, we will have people in charge of ensuring that the place is clean, that the electors are properly distanced. They will see for example these physical transparent barriers that will separate the poll workers,” said Perrault.

Masks will be distributed, hand sanitizer enforced, and disposable pencils required, he added.

According to recent surveys, the number of Canadians interested in casting a ballot by mail could be between two million and three million, compared with about 50,000 during the 2019 election.

Elections Canada is increasing its capacity to process mail-in ballots and it may take longer to count them.

Depending on how the vote goes, it could take up to five additional days after the election for the final results to come in for Canada’s most expensive federal election to date.

With files from CTVNews.ca’s Sarah Turnbull