The minority Liberals will have to create a new income tax bracket for residents earning more than $500,000 if it wants to ensure the support of Ontario's New Democrats to pass the budget.

NDP Leader Andrea Horwath made the recommendation as she released a list of concrete budget recommendations for the first time on Tuesday.

Horwath told reporters that the provincial tax of 11.16 per cent charged on incomes over $78,000 should be increased to 13.16 per cent for those who make $500,000 or more.

The change would bring in and extra $570 million each year, she said.

"As it stands now, the proposed budget asks everyday Ontarians to bear the brunt of balancing the books," Horwath said Tuesday. "This isn't just unfair to families who need a break, it is unfair to all Ontarians."

The Liberal government released its budget proposal last week, which focused on eliminating the deficit in five years, protecting health care and education, and growing the economy.

The Progressive Conservatives immediately vowed to vote against the budget, leaving it in the NDP's hands to vote with the Liberals and support the budget or vote against them and trigger a new provincial election.

On Tuesday, Premier Dalton McGuinty accused the Tories of trying to force an election that no one wanted, adding that another quick election would threaten the province's fragile economic recovery.

Horwath said she wanted to ask voters to gauge their impression of the budget and, a after a series of personal and online consultations, announced her list of amendments on Tuesday.

Horwath said the income created by the new income tax bracket would be enough to cover removing HST from home-heating bills and protect 4,000 daycare spaces, two other NDP priorities.

"Our proposal is going to be to shift the costs of recovery so it is borne more fairly for all Ontarians," she said, adding that she was not "drawing a line in the sand" when it comes to whether or not she would support the budget.

The Liberal budget already included a plan to cut the corporate tax rate from 11 to 10.5 per cent as the province's $15.2 billion deficit is pared down.

But the NDP did oppose a proposed wage freeze for about one million public-sector workers.

McGuinty said he was open to discussing changes, but said any new spending in the budget would need to be covered by new revenues.

With files from The Canadian Press