Decision day is looming for Speaker of the House Gerry Brownlee as he decides whether to put Green MP Julie Anne Genter in front of the Privileges Committee following her parliamentary outburst earlier this week.

Genter has been the subject of numerous complaints from other parties and faces disciplinary action from the Greens after walking across the debating chamber to confront National MP Matt Doocey during a debate on Wednesday night - proceeding to yell in his face before being told to sit down.

The incident was broadcast on Parliament TV during a debate over transport issues, with political commentator Bridget Morten pointing out that Genter's actions couldn't have come during a worse time.

On The Mike Hosking Breakfast, Morten was asked where Genter's conduct ranked on the scale of idiotic moments in Parliament.

"It's pretty high up there," she said.

"In a week where MPs received a pretty significant pay rise, James Shaw was celebrated and had his valedictory speech, you've then got Julie Anne Genter pulling all the limelight towards her over a report that frankly none of us can probably name what they were debating - it's become all about her behaviour."

Due to the nature of her actions, Genter faces the prospect of being reported to the Privileges Committee - a collection of sitting MPs from all parties that determine the punishments for politicians who act out of turn.

Who would sit on the committee is predetermined due to the make-up of parliament - it would consist of three National MPs, two Labour MPs and one representative from the remaining parties.

As explained by former Speaker David Carter, there is due process that needs to be followed by Brownlee before a decision can be made.

"What the Speaker needs to do now - and he's started the process - is collect the evidence, see if anybody else has any extenuating circumstances, then he must decide whether to send it to the Privileges Committee," he told Heather Du Plessis-Allan on Newstalk ZB's Drive show.

"That could be the end of it, but I suspect it's bad this time - that it will go to the committee."

Du Plessis-Allan asked whether it was a slam dunk sending Genter to the committee and, if so, if she would likely be found guilty.

"I agree," said Carter. "As you say, slam dunk. But they must determine what the appropriate penalty should be and the range is huge - they could expel her from Parliament. They're unlikely to do that. They could suspend her for a period of time, they could fine her, they could censure her and require her to come back to parliament and make a very fulsome apology for her actions."

Morten said the process of an MP being sent before the committee was a serious one, but the committee itself is limited in what it can force a sitting politician to do.

She said the most likely outcome would be an apology.

"But an apology only means something if your behaviour changes and we're not seeing indications that might occur."

Former politician Peter Dunne also weighed in on the debate over the possible punishment Genter faces, telling Mike Hosking this morning that the first question was whether or not she had broken privilege.

He said it was a matter for the Speaker to determine.

"She hasn't misled the house and hasn't acted improperly in that sense, it's more a question of conduct," said Dunne.

"What can the committee do? The strongest thing they could do is censure her - which would be more than a slap on the wrist with a wet bus ticket. So a slightly dry bus ticket."

Genter's parliamentary conduct episode has become the latest addition to an increasing list of Green MPs embarrassing themselves and the party in the public arena.

Earlier this year, international headlines were made when Newstalk ZB Plus broke the story that Green MP Golriz Ghahraman had been caught shoplifting from an Auckland boutique store over the Christmas holidays. Two more allegations quickly arose and the MP stood down from her role as a politician.

She appeared before the courts for her actions in March and is set to be sentenced for her actions on June 24.

Among the controversies were current Greens co-leader Chlöe Swarbrick leading anti-semitic chants at a Palestinian protest in Auckland and List MP Darleen Tana having her small business portfolio removed after allegations of migrant exploitation workers at her company.

Morten told Hosking that, to the party's credit, they had acted much swifter on Genter's incident than they had on previous issues.

"They've got to come out pretty strongly and I think, [Genter has] got to fall on her sword with actions like this," she said.

"In terms of the Greens, it's unusual that there's been such a pattern of bad behaviour in such a short time, you've got to ask what they are doing in terms of their pre-selection processes."

Dunne, who formerly led the United Future political party, was more critical of the Green Party's culture, calling it out for portraying a "holier-than-though" attitude and believing they're exceptions to rules.

"I remember a chief of staff for the Greens many years ago - I think this is key to the issue - [he said] 'Of course we're different from other parties because we're a party of principle'. In other words, the rest of you are narrow-minded opportunists," he said.

"But the Greens have that clear, almost like they're on a higher plane than, and so because their cause is so just that almost anything is justified in pursuit of that. And I think that is a part of that mentality coming through. It's an entitlement thing."

Dunne also pointed out that there is a strong crash net for the party due to their unwavering support that remains consistent, even when their MPs fail.

He said the poll results from the last election have a perfect example of how this was shown in the electoral fields.

"When Michael Wood got into his difficulties with the Labour Party over his declarations for personal income, Labour support fell 4 per cent. Contrast that with the Greens - which has had several things go wrong since the election - they are the only party since the election to have significantly increased their support," said Dunne.

"Their support is locked in and hardened. But that doesn't excuse their behaviour."