Premier Dalton McGuinty says he will continue to speak out against the Tories' proposal to extend public funding to faith-based schools in the campaign for the Oct. 10 provincial election.

The Conservatives' push to fund Jewish, Muslim and Christian schools will be an important issue when voters go to the polls, he told reporters at Queen's Park on Wednesday.

"I think it's a really important and defining issue and I'll continue to talk about that during the course of the campaign," he said.

McGuinty said Conservative Leader John Tory's proposal threatens the "social cohesion" developed as children of many religious backgrounds attend school together.

"I don't think that Ontarians believe that improvement or progress is defined as inviting children of different faiths to leave the publicly funded system as we know it and go to their own schools," he added.

"I think that's regressive. I think that takes us backwards. I think our responsibility is to continue to improve the publicly funded system of education."

McGuinty said an important part of Ontario's success as a multicultural society is that the existing public education system lets children of all faiths learn together.

"An important part of our foundation for social cohesion is a publicly funded education system where we invite children of all backgrounds and faiths, economic circumstances, to come together to learn from each other and to grow together," he said.

The premier said his Liberals "will continue to build on the foundation put in place," a publicly funded system, as well as government-funded Roman Catholic schools.

"That's a system that we have inherited," he said of the separate schools.

The Green party is campaigning on a proposal to end public funding of Catholic schools, a practice that has been condemned by the United Nations as discriminating against other religions.