TORONTO - The candidates vying to lead the Ontario Progressive Conservative party will square off today in an hour-long debate in Toronto.

Former Toronto city councillor Doug Ford, ex-MPP and past Ontario health-care ombudsman Christine Elliott, lawyer and businesswoman Caroline Mulroney and social conservative advocate Tanya Granic Allen are competing for the leadership role.

The position was vacated last month when Patrick Brown resigned following allegations of sexual assault.

Ford, the first candidate to enter the race, has set the agenda so far by denouncing the party's proposed carbon tax and promising to revisit Ontario's controversial sex education curriculum.

Political observers say finance and the carbon tax will be key topics today.

They also say the stakes are highest for Mulroney, a rookie politician and relative unknown who must prove she can discuss policy and hold her own against more experienced and forceful rivals.

The candidates will face off again on Feb. 28, in a final debate in Ottawa.