The federal budget is an "all-out assault" on Newfoundland and Labrador and an attempt to punish Premier Danny Williams, which is why six MPs from the province voted against it, says Liberal MP Gerry Byrne.

Byrne, the MP for Humber-St. Barbe-Baie Verte, and five of his provincial colleagues voted against the Conservative budget Tuesday, charging that it robs the province of about $1.6 billion in federal funding.

Liberal Leader Michael Ignatieff said Tuesday he would grant the MPs a "one-time vote of protest" to express their displeasure with the document.

The budget passed by a vote of 211 to 91.

Speaking Wednesday morning on Canada AM, Byrne said Harper has amended the terms of the Atlantic Accord without warning. The Accord protects Newfoundland and Labrador from reductions in equalization payments despite revenue from offshore oil reserves.

"The federal government put a poison pill (in the budget)," Byrne said. "There was an all-out assault on Newfoundland and Labrador and, presumably, on Premier Danny Williams."

Byrne did not elaborate on his allegations that Harper is using the budget to target Williams. However, Williams has fought with Harper in the past about the Atlantic Accord, and the premier ran an "Anybody But Conservative" campaign in N.L. during last fall's federal election.

The strategy worked, as the Conservatives failed to elect a single MP in the province, compared to three MPs in the previous election.

Williams' meddling in federal politics continued last week, as he called on N.L. MPs to vote against the budget after it was tabled by Finance Minister Jim Flaherty.

While Tuesday's move by the six MPs appears to have divided the Liberal caucus, Byrne vowed to stand with his Liberal colleagues against the government.

He also dismissed a suggestion from St. John's Mayor Dennis O'Keefe that Newfoundland and Labrador MPs sit in the House of Commons as a block.

"Together we stand," Byrne said. "Mr. Harper is a divider. He is a divider, and the only way to take this man on, to counter punch what he is doing - not only to the entire country, not only to Newfoundland and Labrador, but to the very fabric of our federation - is we need to be united and stand together."

Rather than showing unity with their party, the MPs who broke ranks and voted against the budget have followed the lead of their premier, which calls into question Ignatieff's authority over his caucus, said CTV's Ottawa Bureau Chief Robert Fife.

"They've done a grave disservice to Mr. Ignatieff," Fife said Wednesday on CTV Newsnet. "They've hurt his leadership right off the get-go on his first test as leader. Basically they said 'we are going to march to the drumbeat of Danny Williams. We are not going to listen to the leader of our party, our leader is Danny Williams.'"

According to Fife, Ignatieff has opened the door for other MPs to be allowed to break party ranks and do the bidding of their respective premiers.

"The fact of the matter is, they're going to say, 'you did it for Newfoundland, we want our one-time coupon to cash it in,'" Fife said. "This is a problem. He's opened a Pandora's box here."