TORONTO -- After weeks of speculation and testing of waters, the Ontario Liberal leadership race finally has a contender.

Premier Dalton McGuinty confirmed Friday that longtime cabinet minister Kathleen Wynne will make a bid to replace him. He spoke just after she announced that she'd resigned her post -- a prerequisite to running for the leadership.

"She's going to be a very strong candidate," McGuinty said in London, Ont.

"I'm very proud of all the contributions she's made to our party, to the government, but most importantly, to Ontarians in her various capacities as minister."

Wynne, who most recently served as minister of municipal affairs and housing and minister of aboriginal affairs, will likely make it official on Monday during a news conference in her Toronto riding of Don Valley West.

The 59-year-old mother of three grown children is openly gay, so should she win the race, she would make history as both the first female and openly gay premier of the province.

McGuinty made the surprise announcement Oct. 15 that he was stepping down after 16 years as Liberal leader, but would stay on until his successor is chosen. That will happen at a Toronto convention the weekend of Jan. 25.

But McGuinty also told his ministers that if they wanted to seek the leadership, they'd have to resign from cabinet first.

Wynne, a former school board trustee, was first elected in 2003 when the McGuinty Liberals took office. She served as education minister from 2006 until 2010, then transportation minister for nearly a year before moving to municipal affairs and aboriginal affairs after the 2011 election.

In 2007, Wynne fended off a formidable opponent, beating former Progressive Conservative leader John Tory when he challenged her in the provincial election.

Other potential leadership candidates said to be considering a bid include former cabinet minister Sandra Pupatello and ex-MP Gerard Kennedy, who lost to McGuinty by just 140 votes in 1996.

Children and Youth Services Minister Eric Hoskins, an accomplished philanthropist who started War Child Canada with his wife Samantha Nutt, was mum on whether he'd challenge Wynne for the top job.

"I'm giving it serious consideration, but I have not yet made a decision," he said Friday.

Hoskins said he has "nothing but the greatest respect" for the "wise" and "experienced" Wynne, whose riding is adjacent to his.

But few contenders have yet to come out of the gate, and the list of potential challengers is rapidly shrinking ahead of the Nov. 23 deadline for declaring their intentions.

Finance Minister Dwight Duncan, Energy Minister Chris Bentley, Education Minister Laurel Broten and Economic Development Minister Brad Duguid have all struck their names from the list.

McGuinty dismissed suggestions that no one wants the job of rebuilding his embattled party, which has been slammed for shutting down the legislature Oct. 15 amid scandal over cancelled gas plants and a criminal investigation into Ontario's Ornge air ambulance service.

"Early days yet," he said. "I know that we're going to have a very hotly contested race. We're going to have lots of experienced people there."

The outcry over prorogation is only one of the burdens Wynne will bear if she wins the Liberal race, said Tory critic Monte McNaughton.

The latest job numbers from Statistics Canada showed Ontario's unemployment rate rose to 8.3 per cent in October from 7.9 per cent in September -- well above the national average of 7.4 per cent.

"Their track record is absolutely despicable in the province of Ontario" with 611,000 people unemployed and a ballooning debt, McNaughton said.

"And worse than that, they're covering up scandals left and right. ... She's got a hell of a track record to defend, one that she can't be proud of."

Wynne has indicated that she was uneasy with the decision to prorogue, saying there was "discomfort" in having the legislature shut.

"Nobody wanted to do that; it's not our first choice," she said Oct. 17. "We want this to go quickly; we want the people's place to be open."

Prorogation brought all legislative business to a standstill and killed planned committee hearings into the cancelled power plants in Oakville and Mississauga, as well as a rare contempt motion against Bentley.

The opposition parties have repeatedly accused McGuinty of proroguing to avoid more bad publicity over the gas plants, especially after the government dumped a second batch of 20,000 documents after the premier and his ministers had insisted all relevant records had been released in September.

The second batch -- following 36,000 documents released Sept. 24 to comply with a Speaker's order -- came just three days before McGuinty announced that he was stepping down and proroguing.

McGuinty has said his successor must decide when to bring back the legislature, insisting he had to shut it down to give his government time to negotiate with angry unions and the Conservatives on a public-sector wage freeze.

He plans to shuffle his cabinet early next week, assigning the municipal affairs and housing portfolio to Bob Chiarelli, who already has transportation and infrastructure.

Bentley, the embattled energy minister who recently announced he wouldn't run for re-election, will take on the aboriginal affairs file.