TORONTO -- Ontario's New Democrats warned Wednesday they would not support any new tax on consumers to pay for billions of dollars worth of public transit expansion in the Toronto-Hamilton area.

"I don't want to see new taxes and (road) tolls that are going to hit household budgets hard," said NDP Leader and Hamilton area MPPAndrea Horwath.

Premier Kathleen Wynne wants to find new "revenue tools" to fund badly needed upgrades to public transit and other infrastructure projects, but the idea could trigger a contentious debate when the legislature returns Sept. 9.

"I've talked about the need for a new revenue stream in the context of the greater Toronto-Hamilton area, and that's the first front we're moving on," Wynne told the Association of Municipalities of Ontario meeting in Ottawa Monday.

The minority Liberals need the NDP's support to stay in power --the Progressive Conservatives vow to defeat the government at the earliest opportunity -- but the New Democrats made it clear they don't like the revenue tools under discussion.

"We acknowledge and recognize and, in fact, believe wholeheartedly that there needs to be significant investment in moving people around in and about the greater Toronto-Hamilton area, as well as other infrastructure needs across the province that need to be addressed," said Horwath.

"Any successful attempt to do that will require the buy-in and the commitment and support of the people of this province, otherwise it will be a fleeting dream."

Hamilton is hoping  money can be found for its estimated $800 million LRT project.

Horwath said the NDP want the minority Parliament to work, but they also want the government to drop plans for corporate tax breaks and to maintain the extra levy on incomes over $500,000 to help fund the transit upgrades.

"We need to have these projects funded, absolutely, but we need to find a fair way of tackling the challenges that we all face as a province," she said.

"People are already very hard pressed in terms of their household budget, and so we don't want to see any particular initiatives that put a bigger burden on them."

Horwath made her comments as she stood beside two freshly minted New Democrats, Percy Hatfield from Windsor-Tecumseh and Peggy Sattler of London West, who were sworn-in Wednesday after winning by-elections Aug. 1.

Hatfield said raising taxes across Ontario to fund transit upgrades in the Toronto region wouldn't go over well in his community.

"Increasing taxes on working families in Windsor, if they're not going to get a benefit out of it, to see other families in the province make a gain, I'm not sure that's going to be something we can sell back home," said Hatfield.

Wynne plans to push ahead with the search for new revenue streams this fall to fund transit in the Toronto-Hamilton area, but rejected the idea of raising property taxes.

"There's a whole range of other options in terms of ways to raise revenue," she said.

"I acknowledge it's not an easy discussion...but it's not something that we can wait another generation for. We have to make those investments."