Parliament's Speaker Gerry Brownlee has referred complaints about Green MP Julie Anne Genter's behaviour in the House last Wednesday night to the Privileges Committee.
The complaints came from National and ACT.
Genter last week apologised after National accused her of intimidating and attacking one of its ministers, Matt Doocey, in the House.
As MPs were debating roading projects as part of the Annual Review - Transport on Wednesday night, Genter rose from her seat and walked across the chamber towards Doocey.
She then waved a book in his face and repeatedly yelled: "Read the report".
National senior whip Scott Simpson told the House that Genter's actions were threatening and unbecoming of Parliament.
Brownlee has received letters of complaint about Genter's actions from Simpson and ACT MP Todd Stevenson.
He told the House he was referring the matter to Parliament's Privileges Committee, which acts as Parliament's court to check MPs' behaviour.
"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.
"The Speaker does not inquire into the veracity of the evidence presented or conduct an inquiry into the allegations; that's the role of the Privileges Committee.
"The Speaker's role in such matters is to determine whether the facts alleged could amount to a breach of privilege or a contempt of the House.
"Accordingly, I find that a question of privilege does arise and that question stands referred to the Privileges Committee."
Genter has not returned to Parliament since her outburst and is currently on a trip to the Chatham Islands, leaving her co-leaders to front reporter's questions this afternoon.
"It's important that she be able to continue carrying on with her work. Disciplinary processes don't stop people from doing their work," Greens co-leader Marama Davidson said.
"She has already apologised for the action in the House which was clearly wrong. We are fronting to that responsibility and putting professional and personal support for her in the disciplinary process."
Greens co-leader Chloe Swabrick said it would not be appropriate for Genter to comment on a matter of privilege anyway.
Genter had been "feeling" the consequences of her actions and would not be losing the transport portfolio, Davidson said.
"She is one of the country's most experienced and passionate MPs when it comes to transport. What is important is she knows that the action in the House was wrong and she's accepting a process to be able to provide support so that this may never happen again."
On Thursday evening, a further allegation of intimidation was made against Genter, by a Wellington florist.
The Greens' co-leaders said they had no prior knowledge of the allegation.