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.

Sunday marks the fifth day of the official campaign, and Horwath made a stop in the Beach neighbourhood Sunday morning, where she spoke about her New Moms Guarantee - which includes protecting maternal and newborn care services, preventing cuts to women's health facilities and the hiring of 360 new midwives.

Horwath also announced that 56 per cent of Ontario's NDP candidates are women - which she said is a political first for Ontario.

Meantime, Premier Kathleen Wynne also spent the day working. The premier took part in the Sporting Life 10K marathon in Toronto Sunday morning, and made several campaign stops in the afternoon.

Doug Ford did not have any campaign events scheduled on Sunday.

- with files from Jackie Rosen