Divisions over the federal budget have claimed their first casualty. Former cabinet minister Joe Comuzzi has been expelled from the Liberal caucus for supporting the Conservative fiscal plan.

Liberal Leader Stephane Dion said Wednesday that parliamentary tradition requires MPs to toe the party line on important confidence votes such as the budget.

"He's not any more part of the caucus,'' Dion said after a caucus meeting.

"A vote on the budget, like a vote on a throne speech, is a vote of confidence. You cannot vote against the caucus on it.''

At the start of question period in the House of Commons on Wednesday, Dion was taunted by Tory MPs with chants of "We want Joe! We want Joe!" before the Speaker restored order.

Comuzzi, a 73-year-old veteran MP for Thunder Bay, said the budget was important for his riding.

"It's for a single issue that's of absolute critical importance to all the people in Thunder Bay and northwestern Ontario, and that's the cancer research centre ... and hopefully it's going to be funded in this budget," he told CTV Newsnet's Mike Duffy Live on Tuesday.

The centre would bring 300 jobs to the struggling city on the shores of Lake Superior. "To vote against it, every citizen in Thunder Bay would be tremendously upset with me," Comuzzi said.

In a written statement Tuesday, Dion said the decision to expel Comuzzi was not taken lightly.

"I encourage the discussion of opinions on matters of policy. However, it is not possible to support this bad Conservative budget and to be a member of the Liberal caucus," he wrote. "Mr. Comuzzi has made it very clear that he will vote in favour of the budget. A vote on a budget or a Throne Speech is always a vote of confidence. The unavoidable consequence of voting against the caucus on these votes is to no longer be part of the caucus."

Comuzzi will now sit as an Independent. He had already announced that he won't seek re-election.

In late February, Ontario MP Tom Wappel broke ranks and voted with the Conservative government on extending two clauses in the Anti-Terrorism Act. However, the Liberals never announced any punishment for Wappel. Dion called it an internal caucus matter.

While the Bloc Quebecois has announced it will support Monday's budget, ensuring its passage, Conservatives are not expected to get much support from the other opposition parties.

The NDP and Liberals are pressing for changes to the government's fiscal package. Some MPs admit that voting down the budget would not sit well with constituents.

Commentators claim that some Quebec Liberal MPs are uneasy about voting against the budget.

They are pleased with a $2.3-billion transfer payment windfall -- that Liberal Premier Jean Charest has already earmarked for tax cuts.

But other provincial premiers call the Harper budget a package of broken promises.

Newfoundland and Saskatchewan say the Conservatives are backing out of deals to share resource and energy revenues. They accuse the Harper government of spending money in central Canada to boost Tory support, ahead of the next election.

On Wednesday during question period, Dion echoed that accusation.

Harper responded that the government is fulfilling its obligations regarding offshore resources under the Atlantic Accord.

"This is an example of why the leader of the Opposition should have read the budget before he took the position on it," said Harper. "If he'd done that, Mr. Speaker, maybe he doesn't have to kick out members of his own party who understand that this is a good budget for Canadians."