Conservative Leader Stephen Harper announced Tuesday night that the Tories would be voting in support of the federal budget on Thursday, but that they would still try to defeat the minority government on a budget amendment.

The amendment in question was part of a Liberal deal to win criticial NDP budget support. It proposes $4.6 billion in new spending on housing and the environment and also proposes a delay in a series of corporate tax cuts. It is also scheduled for a vote on Thursday.

"It's our intention to support Bill C-43, the original budget," Harper said after an emergency caucus meeting Tuesday night, hours after high-profile MP Belinda Stronach defected to the Liberals.

"We'll oppose Bill C-48, which was the deal with the NDP, which is complete irresponsible fiscal policy," Harper added.

Prime Minister Paul Martin has said both bills are confidence matters and that losing either vote would trigger an election.

Before Stronach's sudden departure, Harper indicated he was confident the budget vote would mean a defeat for the Liberal minority government.

But after meeting with the caucus Tuesday night, Harper said he wasn't so sure of the outcome.

"I don't know whether we have the numbers or not," he said.

"But we're going to make every effort to defeat (Bill C48). I think it ultimately will come down to a couple of independents."

While the Liberals may have added to their ranks, the Liberals will still need the backing of two Independent MPs -- Chuck Cadman and David Kilgour -- if they hope to the win the vote.

However, CTV's Rosemary Thompson pointed out that even though Stronach is just one person, her departure could affect how others vote.

"She was certainly one of the rising stars of the Conservative party -- somebody who had leadership ambitions, somebody that people felt was a moderate face of the party, and somebody who can help the Conservatives really win in Ontario," Thompson said.

"So yes, she's only one vote. But she's a lot more than that."

When asked about other MPs who might jump ship, Harper said he was confident there would be no others.

He added that "we'll have a caucus meeting between now and Thursday and make sure everybody's still on board."

After Tuesday's caucus meeting, there was no word on whether anyone else would be defecting.

There are two Conservative MPs from Newfoundland and Labrador -- Norm Doyle and Loyola Hearn -- who are under pressure from Premier Danny Williams to break ranks and support the federal budget to make sure Atlantic revenue deals don't die.

Flanked by Hearn and Doyle, Harper lashed out at Williams on Tuesday.

"They stood by Danny Williams, they stood by Newfoundland, they always will," he said of the MPs.

"And it's about time Danny Williams stood by some of his boys down here too."

"That's the only way Newfoundland and Labrador is going to get anywhere in this country."

He insisted a Conservative government would ensure the province would get its money.

"Danny's going to get his money. The people of Newfoundland and Labrador are going get(their) money," he said.

"And I don't care whether Danny likes me today, or doesn't like me. We'll give the money to the people of Newfoundland and Labrador because they deserve it, and it's the right thing to do."

With files from The Canadian Press