Tory leader Tim Hudak pledged not to raise taxes if Ontarians elect him in the upcoming provincial election.

Hudak put his vow in writing in a formal letter to the Electoral Officer of Ontario on Wednesday, the last day for political parties to declare whether they'll raise taxes if elected to Queen's Park.

Under the Taxpayer Protection Act, established in 1999, Wednesday is the last day for election candidates to formally register a proposed tax hike.

After announcing he wouldn't raise taxes or establish any new ones, Hudak threw down the gauntlet in a message to his Liberal rival.

The PC leader wrote an open letter to Premier Dalton McGuinty stating that in the past McGuinty has promised no tax hikes and then reneged. The letter also reminds McGuinty about the deadline.

Hours later, the Liberals responded with a similar open letter to the electoral officer.

In the message, McGuinty accused the Tories of downloading costs onto municipalities and forcing up property taxes as a result.

The Taxpayer Protection Act doesn't require political parties to disclose future property tax hikes, he noted. McGuinty pledged to change the act to include the mandatory disclosure of actions that may force up property taxes.

The NDP hasn't released a letter but said they are aware of the deadline.

With the official election campaign stretching into its 15th day, the Ontario leaders fanned out across eastern Ontario on Wednesday.

Hudak, McGuinty and NDP Leader Andrea Horwath are all expected to have calmer schedules following the excitement of a tractor race on Tuesday that saw all three candidates squaring off in a hayfield for several hours.

McGuinty started the day with a visit to the Kellogg plant in Belleville. Around noon he was in nearby Georgetown where he was available for photos. The premier will cap off the night in Toronto where he's delivering an evening speech to the Indo-Canada Chamber of Commerce in Toronto.

Horwath promises breastfeeding plan, birthing centres

The NDP leader spent the morning at the Midwifery Collective of Toronto, where she made a health care announcement targeting new mothers.

If elected, Horwath said she'd develop a breast feeding strategy and create four birthing centres staffed by professional midwives.

The location of the birthing centres would be based on need, a party spokesperson said.

With files from The Canadian Press