Dalton McGuinty said his Liberals will not form an alliance with any other party if Ontario winds up with a minority government after the Oct. 6 election.

In an open letter addressed to Progressive Conservative Leader Tim Hudak, McGuinty dismissed recent speculation that he might be planning a minority government coalition with Andrea Horwath's New Democrats.

"I am running to form a Liberal government – and only a Liberal government. There will be no coalition with either your party or the NDP," McGuinty wrote in the letter issued Sunday.

McGuinty's letter comes the same day Hudak warned Ontarians that the Liberals and the New Democrats might join forces to raise taxes if the province winds up with a minority government.

"The Liberals and the NDP: they'll increase taxes and they'll spend money on everything under the sun," Hudak told reporters at a campaign stop in Toronto on Sunday.

Polls across the province show the Progressive Conservatives and Dalton McGuinty's Liberals in a tight race, with both parties in minority government territory.

At an afternoon campaign stop in Toronto, McGuinty repeated his message.

"No accord, no agreement, no entente. What I'm running after is a Liberal government," he told reporters.

This isn't the first time an Ontario Liberal leader has ruled out an accord. After the 1985 provincial election, David Peterson rejected a coalition but later struck a deal with the NDP to bring down the Tories.

Hudak on the offensive

Earlier in the day, Hudak accused McGuinty of plotting "backroom deals" in an attempt to remain premier.

The coalition warnings are evocative of May's federal election in which Prime Minister Stephen Harper warned of a possible Liberal-NDP alliance if the Conservatives didn't receive a majority.

After running the longest minority government in Canadian history, Harper eventually won his majority.

But the political landscape is different in Ontario, where the province is facing a possible minority government for the first time in 26 years.

A Nanos Research poll released Sunday for CTV, the Globe and Mail and CP24 puts the Liberals slightly ahead at 36.5 per cent support, the PCs at 34 per cent.

The poll leaves Andrea Horwath's New Democrats in a potential decision-making role at 26.8 per cent support.

With less than a week to go before voting day, Ontario's two frontrunners are working hard on the hustings, trying to bolster support and break through the dead heat.

At a campaign stop in Toronto on Sunday, Hudak repeatedly used the names McGuinty and Horwath in the same sentence.

He continuously stressed that the pair had similar views on controlling taxes, an issue that's been a pillar of his campaign.

"That debt-retirement charge? Dalton McGuinty and Andrea Horwath -- the Liberals and the NDP -- want to make it a permanent tax grab on your hydro bill," he warned Ontarians.

McGuinty has employed a similar strategy on the campaign trail, lumping his rivals into the same category despite their opposite positions on the political spectrum.

Earlier in the campaign, McGuinty used the phrase "Horwath-Hudak PCs" to refer to similarities between the New Democrats and the Conservatives.

A Liberal TV advertisement shows a photo of Horwath next to a photo of Hudak and implies the two are not that different from one another.

Horwath hasn't said yet whether she'll work with a particular party in a minority government situation.

"Whatever their decision is, I will work hard to make life affordable, to get good jobs in this province, to fix our health-care system," she told reporters Sunday.

Earlier in the day, Horwath released a five-point plan for the New Democrats' first 100 days in government should Ontarians choose to elect them.

Priorities listed in Horwath's plan include:

  • Lowering taxes for small businesses and companies that invest in jobs

  • Removing the HST from "daily essentials" such as hydro and home heating

  • Eliminating waiting lists for home care and acute long-term care

  • Issuing green credits of up to $5,000 for homeowners who retrofit their homes

  • Scrapping corporate tax giveaways

With a report from CTV Toronto's Ashley Rowe