TORONTO - There's no clear favourite yet in the battle to lead the Ontario Progressive Conservatives, but the four contenders vying for the job have boosted the party ranks to about 40,000 members, Tory officials said Friday.

The candidates were racing to sign up new members before Thursday's 10 p.m. cutoff, hoping to line up support ahead of the June vote.

The party wouldn't say how many $10 memberships each candidate sold, but the figures don't say which way the race will go.

"One thing we know: right now, it's a horse race," said executive director Christine Hogarth.

"These numbers do indicate that there's a real horse race for the leadership, which is great. It's exciting and good for the party."

Niagara-area politician Tim Hudak -- who enjoys the support of more caucus members, federal MPs and riding association presidents than any of his rivals -- was deemed to be the front-runner early in the race.

His rivals include Christine Elliott, a Whitby lawyer who is married to federal Finance Minister Jim Flaherty, rural activist Randy Hillier from eastern Ontario, and veteran politician Frank Klees of Newmarket-Aurora, who is making a second bid for the party crown.

None of the candidates would disclose how many memberships they sold -- a key indicator of where they stand ahead of the one-member, one-vote election.

The Conservatives had about 8,500 members before John Tory stepped down as leader in March and triggered the race, though that figure doesn't include many people who bought memberships through their riding associations, said party president Ken Zeise.

The list of party faithful now tops 40,000, but it's still far less than the 100,000 members counted during the 2002 race, when the Conservatives were in power and choosing a new premier.

"Forty thousand is a healthy number," Zeise said.

But that number could be deceiving, said politics professor David Docherty of Wilfrid Laurier University.

Conservatives often renew their lapsed memberships during leadership recruitment drives, he said.

"The question is, how many of those folks will stay active two or three years from now?" Docherty said.

"If they are to keep 75 per cent of that going into the 2011 (provincial) vote, that's more impressive than signing up 40,000 now."

Candidates had only a few short weeks to sign up new members, which may account for the less-than-impressive turnout, he said. The short race -- which dismayed many elected Tories, including Klees -- also shut out tentative leadership hopefuls who needed more time to test the waters.

The party will vote for a new leader on June 21 and June 25, using ballots that will ask voters to rank the candidates in order of preference. Ballot boxes will be sealed and sent to the convention, taking place June 26 to 28, to be counted.

With Hudak likely in the lead, the other three candidates will be jostling for position on the preferential ballot, Docherty said.

"If you're Christine Elliott or Frank Klees, you know that you're not going to get a lot of so-called first-ballot support, so you want to make sure that people have ranked you second," he said.

Securing that No. 2 spot could be crucial for victory if none of the candidates wins a clear majority in the first round, he said.

"People who rank Frank first -- she'll want to be ranked second, so that if she lasts long enough, those votes come to her."

All four candidates have also used their membership drives to fundraise for their campaigns.

Hudak's team said he's raised nearly $200,000 in contributions, though only $20,000 has been disclosed by Elections Ontario so far.

By law, leadership candidates must report all campaign contributions over $100 to the agency within 10 business days, which are then disclosed on its website.

Elliott reported $186,100 in contributions, while Hillier reported $91,809 -- including $25,000 of his own money. Both camps say the money represents a fraction of the overall amount they've collected since the race started in March.

Klees collected $62,567, according to Elections Ontario. His spokeswoman Sandra Buckler said Klees has actually raised more than $300,000, though not all the donations have been collected.