Canadians can begin casting their ballots through advance polls starting Friday, taking advantage of a voting option that has become increasingly popular -- and inclusive -- since its introduction more than 90 years ago.

Elections Canada spokesperson Grace Lake said advance polling is designed to give Canadians a more convenient option when they exercise their right to vote.

"The purpose of the advance polls is to give greater access, greater convenience for the eligible elector to vote," Lake told CTV.ca in a recent telephone interview from Toronto.

Lake said 4,700 advance polls will be active across Canada from noon until 8 p.m. on Friday, Saturday and Monday.

The Canada Elections Act decrees that advance polls occur on the 10th, 9th and 7th days before polling day, which has landed them in the midst of Easter and Passover.

While the timing is unfortunate for those celebrating religious holidays, Lake said electors can still vote alongside the rest of the electorate on May 2, or via special ballot.

"We recognize that many electors will find the advance polling dates inappropriate or inconvenient and we fully understand their concerns," Chief Electoral Officer of Canada Marc Mayrand said in a recent statement.

"It is important that electors choose the voting option that best suits their individual circumstances."

How many people will turn up to advance polls over the weekend is unknown, but if recent history is any guide, as many as 1 million voters, or even more, are likely to cast their ballots early.

For the past two elections, more than 1.5 million Canadians voted via advance polls, accounting for one in 10 votes cast in the 2006 and 2008 elections.

That was an increase over the 1.2 million Canadians who cast valid votes in the 2004 election that reduced the Paul Martin-led Liberals to a minority government.

Advance polls were first introduced in Canada in 1920, though they weren't nearly as accessible as they are today.

The Elections Canada website indicates that only sailors, railwaymen and commercial travellers were initially allowed to use advance polling.

But after the 1921 election, Oliver Mowat Biggar, the country's first-ever chief electoral officer, pushed to have more advance polls available to voters.

Over time, "airship" workers, as they were called before the term aircraft was used in the law, fishermen, businessmen, RCMP members and soldiers also gained the right to use advance polls.

In 1960, the rules were relaxed to allow anyone to vote by advance poll, as long as you believed you would not be able to otherwise make it to the polls on election day. Then you had to swear an affidavit to prove it. (The affidavit rule remained in effect until 1977.)

Because of this amendment, nearly 100,000 people cast ballots through advance polls in the 1962 election, a ten-fold increase over the average of previous elections.

Canadians would go back to the polls within six months of the 1962 election, however, when the Progressive Conservative government led by John Diefenbaker fell to the Liberal government of Lester Pearson in the spring of 1963.

All voters were allowed to use advance polls as of 1993, whether they were going to be around on election day or not, which paved the way to large swaths of the Canadian public voting this way in the years that followed.

Some 775,000 voters used advance polls in the 2000 election, which was a 10 per cent jump above the 700,000 who did so in 1997.