Tempers flared Wednesday over the government's mammoth omnibus budget bill, as Conservative and NDP MPs exchanged angry words and aggressive gestures in the middle aisle of the House of Commons.

Bill C-45 passed at report stage on Tuesday night in a six-hour voting session.

But Wednesday, NDP House Leader Nathan Cullen raised a point of order, demanding that the key final vote, out of the 46 separate votes that happened Tuesday, be done over because the minister of finance, the sponsor of the bill, had not been in his chair.

House of Commons cameras reveal what looks like a heated exchange between Government House leader Peter Van Loan and Cullen. No sound can be heard, but Van Loan can be seen crossing the floor to remonstrate with Cullen. Van Loan can be seen kneeling down, shaking his finger at Cullen.

NDP Leader Thomas Mulcair sits beside Cullen in the House, but is out of camera range. However, other MPs have said that Mulcair used "unparliamentary language" directed at Van Loan, while other reports say Van Loan was swearing. Cullen told the CBC News Network's Power & Politics host Evan Solomon that Van Loan said things to him that he couldn't repeat on TV.

Van Loan told CBC News that after Mulcair "exploded," he went down on one knee to "focus" his conversation with Cullen.

"I certainly pointed my finger at Nathan, but that was it," the House leader said. "I may have used one inappropriate, colourful word, but that's no big deal. It's nothing he hasn't heard before I'm sure."

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Government House Leader Peter Van Loan was involved in a heated exchange with NDP House Leader Nathan Cullen and Opposition Leader Tom Mulcair in the House of Commons Wednesday that saw other MPs step in to restore order. (CBC)

Liberal MP Ralph Goodale witnessed the entire incident, but wasn't close enough to hear what was being said. Goodale told CBC News that "the body language was very unparliamentary."

Goodale said at one point he turned to the sergeant-at-arms and said, "We may need you." It was, said Goodale, "a nasty little set-to."

On the tape, Conservative MP Gary Goodyear can be seen walking over to Van Loan and Cullen, and then Minister of Defence Peter MacKay is seen trying to herd both Goodyear and Van Loan back to the Conservative side of the House. He says that Mulcair told Van Loan, "Don't threaten my House leader."

Goodyear, minister of state for science and technology, told CBC News later Wednesday evening that he was "protecting people from the werewolf."

"Gary's a funny guy," Van Loan told CBC.

Later, Conservative MP Shelly Glover, once microphones were turned back on, said that "boys are being boys" and that everyone should get back to talking about the budget.

Whip allowed finance minister to leave

"I voted on almost all the votes last night and the whip told me I could leave, which is what I did," Flaherty told CBC News Wednesday evening.

Flaherty laughed off suggestions Van Loan was trying to defend his honour, saying Tuesday's vote was a "procedural vote" while the vote at third reading on Wednesday was the "substantive" vote.

Deputy Speaker Joe Comartin, who is a New Democrat, was presiding over the Commons at the time of the vote Flaherty missed.

"This is a regular occurrence. [A minister being absent] is nothing unusual," said Tom Lukiwski, Van Loan's parliamentary secretary. "We didn't think [Cullen's point of order] was necessary."

"The Speaker takes a look, if that minister is not there, they just arbitrarily pick another minister and move on," he said.  "That's what should have happened last night. It didn't, unfortunately."

"I've got all the respect in the world for Joe Comartin," Lukiwski said of the deputy Speaker, who only took on the role this fall after the retirement of former MP Denise Savoie. "But he's new to the job, he's learning his job. It was an honest mistake."

In ruling against Cullen on Wednesday, Scheer confirmed Lukiwski's account of what how the Commons usually proceeds in a minister's absence and called the error a "minor oversight."

Commons Speaker Andrew Scheer said clerks were aware of Flaherty's absence that evening and the House of Commons journals had already been amended to record Van Loan moving the motion on Flaherty's behalf.

Van Loan told CBC News that he thought it was "very inappropriate" for the NDP to be portraying an error made by their own deputy Speaker as an error made by the government and he originally approached Cullen to "express [his] disappointment" for the point of order considering it was Cullen's own caucus member who made the mistake.

Van Loan said he felt constrained in not being able to describe in detail the error made by Comartin in his Commons response to Cullen's point of order. "You don't want to discredit the Speaker. You don't want to discredit the House officers," he said.

"Normally I get along very well with all the house leaders," Van Loan said.

Wrangling before final vote

Cullen's point of order was the kind of procedural wrinkle that many were predicting might emanate from the opposition as the budget bill near its final vote. 

The Liberals' Goodale noted that if the vote had to be redone, the bill would have to wait another day to proceed to third reading because two stages of a bill can't be done in one day.

Despite hundreds of amendments introduced by the opposition parties, the 400-page bill survived without any changes. Not surprisingly, every single amendment was voted down by government MPs.

The bill is actually the second part of Budget 2012 and is meant to implement the changes introduced in Finance Minister Jim Flaherty's spring budget bill.

As the hours passed Tuesday night, the NDP "slow voted," meaning each vote was accompanied by much buttoning of jackets and sips of water, but the voting was all over by 10 p.m. ET.

NDP's 'chalk circle' on budget bill

In question period on Wednesday, Flaherty said, "Canadians should be disappointed in the NDP and their reckless opposition allies in the tactics to try to delay [the] bill."

Mulcair chose a metaphor to describe his party's purpose in dragging out the vote. "It's a bit like when you go to the dry cleaner's, and you've got a spot, and you see the dry cleaner put a little bit of a chalk circle around it."

Mulcair explained that his party was shining a spotlight on what it sees as the excesses of the bill. In particular, he mentioned the gutting of the protections offered by the Navigable Waters Protection Act which were inserted into a bill that's about the budget. In fact the removal of many lakes and streams from federal protection was never mentioned in the original budget bill last March.

"We've been blessed in this country with hundreds of thousands of lakes, tens of thousands of rivers that used to be protected. They no longer are."

But, said Mulcair, certain lakes are still covered, especially, he said, if they are in the area of a byelection the Conservatives recently won in Durham, or if they are in Treasury Board President Tony Clement's riding. "Lakes for millionaires are going to be protected, but lakes that are important across the country are no longer protected unless you're in a Conservative region."

Interim Liberal Leader Bob Rae described the six hours of voting as a "night of symbolism." Rae admitted that he and his MPs don't like having to go through the long process of symbolic voting, but said it's a result of frustration because the government refuses any real debate or discussion.

"[The Conservatives] have not accepted any amendments. They've not accepted any suggestions. They've not accepted any improvements. They've made no changes. So it's pretty hard for them to expect anything but tough response from us in terms of the kind of time that it’s going to take to get to a solution," Rae said.

Flaherty said he was pleased his bill is wending its way through the House, saying it was good for jobs, growth and the economy: 

"The economy is growing modestly now so anything we can do to spur it along especially in job creation, which the new credit for small business is, is in the bill. So that helps. It worked last year. It will work again."

"We got it done," Flaherty said.

With files from CBC News