National MP Sam Uffindell has been stood down from the party's caucus while an investigation is done into further allegations of bullying raised by RNZ.
A woman who flatted with the Tauranga MP at university in 2003 says Uffindell was an aggressive bully who once pounded on her bedroom door, screaming obscenities, until she fled through her window.
In a statement issued late last night, Uffindell denied claims he engaged in "intimidatory or bullying" behaviour, but said there was a falling-out between flatmates.
The allegations follow revelations that Uffindell, as a teenager, beat up a younger boy at Auckland's prestigious King's College boarding school and was asked to leave.
The MP yesterday described himself as a 16-year-old thug but said he was now a changed person. RNZ has spoken to his former flatmate and her father.
They did not want to be named.
National Party leader Christopher Luxon released a statement late on Tuesday night.
"This evening my office became aware of very concerning accusations made to RNZ about behaviour shown by Mr Uffindell toward a female flatmate in 2003 while at university," he said.
"Mr Uffindell disputes the allegations and in the interests of natural justice, an independent investigation will now be undertaken to determine the facts. While this process is underway, Mr Uffindell will be stood down from caucus.
"The investigation will be conducted by Maria Dew QC and I expect it to take two weeks.
"However, as these allegations have only come to me in the last few hours, the finer details of the investigation, including the terms of reference, are yet to be confirmed and will be finalised over the next couple of days."
Uffindell has also responded and said when he was a student at Otago he enjoyed a student lifestyle, which included drinking and, at times, smoking marijuana.
While in second year a number of flatmates fell out - and two of the flatmates left midway through the year.
He rejects any accusation that he was engaged in behaviour that was intimidatory or bullying. he says it simply did not happen.
Uffindell said while there is an investigation into these accusations he will not make further comment.