The Ontario New Democrats and the Progressive Conservatives are attacking Liberal Leader Dalton McGuinty for skipping a Friday debate focused on northern issues.

The hour-long debate in Thunder Bay got underway at 11 a.m. and is being hosted by a group of municipal and business groups.

McGuinty has said he cannot attend because of a scheduling conflict and said the Liberals never received an alternate date from the debate organizers.

But his absence speaks volumes about how the Liberals regard the north, said NDP Leader Andrea Horwath.

"People are feeling ignored by the provincial government," she said Friday.

"The premier is not even coming to northern Ontario for the debate. I can't imagine they'd be nothing more than extremely disappointed at the least and probably quite angry and insulted."

The debate presents a big opportunity for both the NDP and Conservatives to gain seats in the region, and is also a dry run for two leaders who have never debated each other during an election.

Progressive Conservative Leader Tim Hudak said the debate is important because it is an opportunity to talk about problems in the North.

"Whole communities being wiped out with mill closures ... and Dalton McGuinty has turned his back on Northern Ontario," he said.

McGuinty said there's plenty of opportunity to focus on the north in a televised debate scheduled for Tuesday. He's also said having a debate focused on the issues for a particular region would allow leaders to use a regionally-tailored message that they would never use in another part of the province.

The Liberals did offer a candidate to take McGuinty's place, but the organizers did not take them up on that offer.

The debate was not open to the public.

McGuinty is campaigning in Toronto, Hamilton and Kitchener on Friday.