Green MP Julie Anne Genter has been referred to the Privileges Committee after her outburst in parliament last week, Speaker Gerry Brownlee has confirmed.

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 last Wednesday night, yelling in his face before being told to sit down.

It was broadcast on Parliament TV during a debate over transport issues.

Political commentator Bridget Morten pointed out that Genter's actions could not have come during a worse time.

"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."

Today, Brownlee confirmed that Genter's punishment will be decided by the Privileges Committee - which is made up of a selection of sitting MPs within the house representing all elected parties.

In delivering his ruling, Brownlee said he had received letters from National Party whip Scott Simpson and Act Party whip Todd Stephenson about Genter's behaviour confronting National MP Matt Doocey in Parliament.

"The conduct complained of could amount to threatening or intimidating a member acting in the discharge of their duty, or threatening a member on account of their conduct in Parliament."

He said it was not for the Speaker to look into the veracity of the evidence or conduct an inquiry into the allegations. That was the role of the Privileges Committee. He said his role was to decide whether the conduct could amount to a breach of privilege, or contempt of Parliament.

Last week, Morten told NewstalkZB the process of an MP being sent before the committee was a serious one, but the committee itself was limited in what it could 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 parliament speaker Sir David Carter told Newstalk ZB that Genter appearing before the committee would be a "slam dunk" in terms of punishment, but the possible consequences she could face would vary.

"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," he said.

Former politician Peter Dunne told the Mike Hosking Breakfast this morning that the first question was whether Genter had broken privilege.

"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 has become the latest addition to an increasing list of Green MPs embarrassing themselves and the party in the public arena.

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

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

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