TORONTO - The leaders of Ontario's three main political parties square off Thusday in a debate that will see Premier Dalton McGuinty attempt to deflect attacks on his track record.

Progressive Conservative Leader John Tory says while he'll try to sell his platform to the voters, it's also his duty to question McGuinty's record of broken promises.

McGuinty says he hopes the televised debate, which begins at 6:30 p.m., amounts to more than just jousting with his opponents.

The Liberal leader says he wants to explain to voters what his government has achieved.

Tory's pledge to expand the role of private health care within the public system could also find its way onto the debate agenda.

McGuinty lashed out at the idea Thursday, saying it shows Tory's preference for the private sector.

NDP Leader Howard Hampton has said he'll focus on hiring more doctors and providing better treatment for seniors as a way to ease the crunch in hospital emergency rooms.

The debate will last 90 minutes and comes as the latest Canadian Press Harris-Decima poll suggested the Liberals maintained a lead over the Conservatives through the first week of the election campaign.