OTTAWA -- Conservative leadership candidates are working on getting out any remaining votes ahead of Saturday's final event in Toronto, at which the party will announce the successor to Stephen Harper.

Officials estimate they've already received 125,000 ballots from the party's 259,010 members, or nearly 50 per cent turnout. That sets a Canadian record for votes cast in a leadership race, besting the Canadian Alliance's 120,000 votes in 2000 and the more than 104,000 votes cast in the 2013 Liberal leadership that elected Justin Trudeau. The last Conservative Party race in 2004 saw about 97,000 ballots cast. Voter turnout for the 2013 Liberal leadership race was more than 80 per cent.

That number of votes "makes this the largest leadership race in Canadian history," said Conservative Party spokesman Cory Hann.

Another 2,000 members have registered to be there in person to see the party announce its next leader.

It's the last week for voting in the contest, which officially started last March. The party's auditors, Deloitte Canada, must receive the votes by Friday at 5 p.m. unless members vote in person at one of the few local polling stations or at the main event in Toronto. For much of Canada, that means ballots must have been cast before this week.

Most votes already cast

Still, the leadership contestants' teams are working on getting out their remaining vote, with some prepared to courier ballots to Deloitte's office in Vaughan, north of Toronto. They've also set up mobile voting stations to help members with their ballot packages, which require a signed declaration and a photocopy of the voter's ID in order to count.

Maxime Hupé, spokesman for Quebec MP Maxime Bernier's campaign, said they're using automated robocalls, volunteer phone calls and emails to reach anyone who still hasn't voted, and they've got volunteers ready to pick up ballots to be couriered. They may in some cases physically bring some ballots to Toronto, he added.

"At this stage of the race, I think most people who had the intention of voting already did... it's just in this final stretch when we want to grind as [many] votes as possible," Hupé said.

Bernier has wrapped up campaigning, but hosted a cocktail party in his Beauce riding, and is working on speeches for Friday and Saturday nights, he added. The libertarian candidate has consistently polled at the head of the pack and increased his organization when celebrity businessman Kevin O'Leary dropped out of the race to endorse him. Bernier is widely considered the frontrunner, although the race is tough to predict given the preferential ballots and the points system used by the party.

Nancy Bishay, spokeswoman for Saskatchewan MP Andrew Scheer, says the work to get-out-the-vote has been going on for weeks.

"Our supporters are coming out at a higher rate than we expected. And to me that means the race is going to be really tight, so we are just continuing to work on making sure all the votes are in," she said.

"It's been clear that Andrew's been right up there with first ballot support, and he's got a lot of second and third ballot support. So anything can happen."

Some packages missing key pieces

The mail-in ballots could complicate the counting process. Members need to include the copy of their ID, as well as their signed declaration, in an envelope separate from their ballots. Bernier's campaign says its scrutineers noticed up to one fifth of ballots didn't have copies of ID or the declarations included in the main envelope.

Deloitte officials started opening the envelopes on May 15 to check for the identification. Hann says they'd processed about 25,000 ballot packages as of last Friday, and found about one in 10 hadn't enclosed the ID and declaration in the main envelope. Those were set aside and then opened under the observation of the party's deputy returning officer and the candidates' scrutineers. About 60 per cent of the set-aside packages simply had the ID or declaration in the wrong envelope, so those will be counted. Hann says about four per cent of all the ballots received don't have the documentation needed for the vote to count.

"They're not necessarily spoiled because someone could decide, you know what, I realize I may have sent without this information, can I get another ballot or can I vote on the day of, and in those cases we'll do that," he said.

For the remaining four per cent, Hann said the campaigns' scrutineers can notify those members that they didn't properly complete the package.

The ballots will be kept in sealed boxes until Saturday, when they will be transported to the Toronto Congress Centre, the site of the leadership event. Officials and volunteers will start opening the ballot envelopes at 4 a.m. and start processing them through the counting machines at 6 a.m.

Stragglers in Toronto can vote at the congress centre from 10 a.m. to 4 p.m. ET on Saturday.

Some local riding associations have set up in-person polling stations, but they're few and far between because the associations have to pay the costs for them. Several Edmonton-area ridings have organized a polling station, with others in Winnipeg, Moncton, across Ontario and one in Montreal. Members can vote at any polling station.

Points awarded based on percentage of votes

The results will be announced Saturday starting around 5:45 p.m. ET, with the new leader likely to be announced by 7 p.m. and ready to give a speech to the audience. The party will group several rounds at a time as contenders with the least points are dropped from the ballot and their support redistributed.

The Conservative Party uses a points system that gives each riding 100 points, no matter how many members it has. Contestants will be allocated points based on their share of the vote in each riding, and have to win 16,901 points in order to win the leadership.

If nobody wins on the first ballot, the person with the least points is dropped from the contest. Those who vote for that person will have their votes redistributed to their second choices to see if anyone has hit the 16,901-point threshold. If not, the process is repeated until somebody has won more than 50 per cent of the possible points.

The leadership event kicks off Friday evening with a candidate showcase, which will give all 13 contestants one last chance to speak to members.