OTTAWA -- Canadians who refuse to wear a mask for non-medical reasons may be barred from casting ballots in person on Sept. 20.

In places where local public health rules require masking, Elections Canada will enforce those rules at polling locations, chief electoral officer Stephane Perrault said Wednesday.

"If you have a medical reason not to wear a mask then you will not be denied the right to vote," he told a news conference.

"But if it's just a matter of personal choice and the mask is mandatory in the jurisdiction in which you are voting, then we will apply those rules."

Perrault encouraged all those who cannot or will not wear a mask to vote by mail instead, arguing that such electors have a responsibility to plan how they intend to vote in the midst of the COVID-19 pandemic.

At the same time, Perrault defended Elections Canada's decision not to require some 250,000 poll workers to be fully vaccinated, although that could change if the pandemic worsens.

"These are the same people that you meet every day at the grocery store. The difference is that the polls are a controlled environment where safety measures can be applied more rigorously," he said, adding that he expects most poll workers will be fully vaccinated in any event.

Perrault said Elections Canada is continuing to consult with public health authorities "and we will adjust our measures based on their recommendations."

"The recommendations so far do not include making vaccinations mandatory."

He pointed out that chief public health officer Dr. Theresa Tam has said it's "perfectly safe" to vote in-person as long as proper public health measures are in place.

For the Sept. 20 federal election, all poll workers will be required to wear masks and they'll be behind Plexiglas barriers. Masks, hand sanitizer and single-use pencils will be provided to voters, who will be required to keep physical distance.

Because of the pandemic, Elections Canada is expecting up to five million voters may choose to vote by mail -- a dramatic increase over the 50,000 who chose that option in 2019.

Elections Canada will not start counting most of those ballots until the day after the election and it could take up to five days to complete the count. That means Canadians, who are accustomed to learning the outcome of elections on election night, could be left in suspense.

"If it's a very tight race and there's a large number of postal ballots, then it can take a few days to find out who is the actual winner," said Perrault.

He also warned that voters could find they have to travel a bit further afield to cast votes in some unusual polling places, like movie theatres. That's because some of the usual polling locations, like schools and recreation centres, are more reluctant to open their doors to voters during the pandemic.

This report by The Canadian Press was first published Aug. 18, 2021.