Ontarians are facing another threat of an election call after the opposition parties joined together to force changes in the Liberal government's budget bill.

At a news conference Friday morning at Queen's Park, Premier Dalton McGuinty repeated his threat to call an election if his budget bill is changed.

McGuinty said he wouldn't set an "artificial timeline" on when the budget needed to be passed, but he made it clear he will not accept opposition interference.

On Thursday, as the legislature was preparing to rise for its summer break, McGuinty issued the threat and accused NDP Leader Andrea Horwath of reneging on a deal reached earlier this spring to back the budget bill in exchange for some changes, including a new tax on Ontarians earning more than $500,000.

'I don't think it's helpful or productive for Ontarians to engage in this game of brinkmanship and threats over an election.'—Andrea Horwath, Ontario NDP leader

The minority Liberals need the support of the NDP to get their budget passed.

McGuinty told the news conference he spoke with Horwath on Thursday and told her she doesn't need to like "the whole darned budget."

"The original agreement we had was not that [the NDP] would support the budget, but that it would not block passage of the budget. Now Ms. Horwath is saying, 'Well I am going to support the budget.' But at the same time she's saying, 'But I will work to block passage of individual components of the budget,' which I call essential tools to delivering on the budget."

Premier Dalton McGuinty says he'll call an election if the budget changes aren't reversed. (Chris Young/Canadian Press )

The premier said "if we cannot pass this budget, we will take it to the people in a general election."

But in an interview with CBC News on Friday morning, Horwath said McGuinty is losing credibility by crying wolf every time he hits a snag.

"It's unfortunate, however, that every time there's a little bump in the road, the government decides to jump on the campaign trail — Mr. McGuinty threatens an election.

"I'm prepared to find a way to get to Wednesday and pass the budget. I don't think it's helpful or productive for Ontarians to engage in this game of brinkmanship and threats over an election," the NDP leader said.

Horwath says the premier isn't getting it right and she isn't doing anything she didn't say she would do. McGuinty's threats, she said, aren't helping the situation.

"We wanted to get the budget into committee so that we could make some further improvements. I told the premier that. I told the public that. I'm keeping my word ... and I think that him rattling the sabre on an election is not the way to go forward here."

The Liberals say the opposition parties got together on Thursday and killed about 25 per cent of the budget bill.

Election call would make people 'livid'

Also speaking to CBC News on Friday morning, Ontario Finance Minister Dwight Duncan called the situation "bizarre."

He said the schedules voted down by the NDP and the Conservatives could add $3 billion to the budget — money that would have to come from somewhere, either cuts or increased taxes.

"Ontarians will be livid if there's an election," he said. But, he added, "we have until Wednesday to straighten this out."

Horwath says the changes the NDP want — and the Conservatives have supported — are necessary to protect the province's environmental laws. If the legislation passes as is, she says, the chances are Ontario will have another Ornge air ambulance scandal.

"There are schedules in that legislation that guts our environmental protection in Ontario .... we're doing what we said we would do all along. These concerns are serious concerns," she said.

"It takes away all kinds of public oversight from the government, so the government basically privatizes or devolves all kinds of government functions to outside agencies and organizations without any legislative review, simply with the stroke of a pen of a cabinet minister. That's not acceptable," she said. "The government hasn't learned from the mistakes of Ornge."

PC Leader Tim Hudak compared the dispute to a soap opera and said he expects the New Democrats will support the Liberals.

The legislature adjourned on Thursday, with MPPs agreeing to regroup next Wednesday to vote on the budget bill.