MP Bill Casey was booted out of the Tory caucus hours after he broke ranks with his party on Tuesday night and voted against a bill to implement the federal budget.

The Nova Scotia MP said he couldn't support the budget because it doesn't allow his province to fully benefit from offshore oil and gas revenues without losing equalization payments from the federal government.

Bill Casey votes against the bill to implement the federal budget.
(CBC)

When Casey rose to his feet to cast his "Nay" vote, cheers and shouts erupted in the House of Commons.

"In some ways, it was very difficult, in other ways, I just don't think I have any choice," Casey said after the vote.

Casey will now sit as an Independent MP.

Finance Minister Jim Flaherty and Foreign Affairs Minister Peter MacKay, who is also a Nova Scotia MP, tried to get Casey to change his mind with the promise of another deal for the province.

"They've got a deal on the go," Casey said. "But it's so complicated. With one minute before the vote, I could not figure out what it was. It was complicated. All I know is, it wasn't the Atlantic Accord."

The budget implementation bill, which sets the Conservative's March 19 budget into action, still passed by a margin of 158-108. It was a preliminary vote, with a third and final reading of the bill expected later this week.

Bloc Québécois MPs and all Conservatives except Casey banded together to ensure the bill passed on Tuesday. The Liberals and the NDP voted against it.

Casey, a veteran backbencher, said the government had promised Nova Scotia and Newfoundland and Labrador that it wouldn't include offshore oil and gas revenues in its equalization formula.

"I believe that the government of Canada signed a contract with my province of Nova Scotia and it's not being honoured," Casey told CBC News earlier Tuesday in Ottawa.

"Whether it's by accident or not, the budget was amended, and that amendment was not agreed to by the provinces, who also signed it. So only one side of this agreement changed it and approved this amendment.

"I don't think that's right."

Casey wanted Flaherty to make changes to the budget before the third reading, but Flaherty rejected calls Tuesday in the House of Commons to do so.

The current budget offers the two provinces a choice between two options:

• A new, enriched equalization formula that includes a cap on the amount of offshore oil and gas revenues the provinces can keep.
• The old equalization formula, with the benefits from the Atlantic Accord on offshore oil and gas revenues that was negotiated by the former Liberal government in 2004.

Casey, who was first elected to Parliament as a Progressive Conservative, said the new budget could cost Nova Scotia up to $1 billion.

Opposition MPs from the region said Casey showed courage by voting against the budget.

"For Bill Casey to have to take the brunt for it and have to carry the weight for Nova Scotians, it's just despicable," said Nova Scotia Liberal MP Mark Eyking.

"I think any self-respecting Nova Scotian or Newfoundland politician from any political stripe has an obligation to vote against the budget that sticks it to Atlantic Canada," said Nova Scotia NDP MP Alexa McDonough.

With files from the Canadian Press