TORONTO -- Ontario's NDP leader won't commit to forming a coalition government with the Liberals should the Progressive Conservatives win a minority in the upcoming provincial election.

Andrea Horwath says that at just under a month until Ontarians hit the polls, it's too early to make any definitive decisions.

Her comments come as the New Democrats are gaining traction in the polls, with some suggesting she's the top challenger to Doug Ford's poll-leading Tories.

Horwath maintains that her party could win a majority of seats, but says that if things go another way she would be unwilling to work with any party that wanted to roll back corporate taxes.

But she also says the party won't make any decisions of that nature before knowing the results of the June 7 election.

It's the fifth day of the official campaign, and Premier Kathleen Wynne also has scheduled events.

Ford will return to the campaign trail on Monday.