TORONTO - The race to replace John Tory as leader of Ontario's Progressive Conservatives will expand to three candidates Thursday when Tim Hudak formally announces his campaign, The Canadian Press has learned.

Hudak will launch his leadership bid with a news conference at the Ontario legislature and then hold an event Thursday night for supporters in his Niagara West-Glanbrook riding, sources said.

The 41-year-old Hudak, currently the party's finance critic, will have about 12 of the 24 Conservative caucus members on hand to show their support when he launches his campaign.

"He's got a pretty good chunk of caucus support, which we're very happy about," said one source with Hudak's campaign.

"That amount of caucus support right off the bat shows that the team at Queen's Park has a lot of faith and trust in Tim."

With interim leader Bob Runciman and deputy leader Elizabeth Witmer both remaining neutral, Hudak will start the race with more than half of the caucus members listed as supporting his bid for the party's top job.

Hudak was first elected in 1995 and was minister of northern development and mines and minister of tourism, culture and recreation under former premier Mike Harris. He was later named minister of consumer and business services by then-premier Ernie Eves.

Hudak was born and raised in Fort Erie and educated at Notre Dame College School in Welland. Before entering politics, he worked in the tourism and economic development business and was a customs officer at the Niagara border with the U.S.

Fellow caucus members Frank Klees and Randy Hillier have already announced their intentions to try to succeed Tory as leader of Ontario's Conservatives.

Christine Elliott, the wife of federal Finance Minister Jim Flaherty, has also been testing the waters for her own possible run for the party leadership.

There has also been talk about some federal Conservatives considering bids to lead the Ontario party, but so far all those believed to be possible candidates have said they like their jobs in Ottawa.

Tory's inability to get a seat in the legislature was one of the main reasons he couldn't rally the caucus behind him, and it's believed any leadership candidates who don't have a seat would be at a significant disadvantage compared with their caucus rivals.

Tory resigned in early March after losing a Lindsay-area byelection in a Conservative-held riding to the governing Liberals, throwing the official Opposition party into a leadership race.

Harris has been working the phones drumming up support for Hudak, who has been considered the likely front-runner in the race ever since Tory stepped down.

However, the sources said Harris would not have any official role with Hudak's campaign.

Hudak's wife Deb Hutton was the former chief of staff to Harris and a high-profile member of the party.

The Conservatives will announce their new leader at a convention in Markham on June 27 after a vote by party members across the province the previous week.