The investigation into Meka Whaitiri is understood to involve shoving.

The former Customs Minister has been stood down, while an investigation is carried out into an alleged altercation between her and a new staff member.

It is believed the person at the centre of the allegation is a staff member in a media-adviser position, who had been in the role for less than a fortnight.

Former Labour Party President Mike Williams told Mike Hosking if it's proven that an assault took place, then it's a sackable offence.

"Assault is a very broad kind of word though, and my understanding is that if it involved shoving, it is assault."

He says one of the issues is the lack of training for ministers.

"I think it's probably lack of supports, ministerial services don't seem to think it's their job to give these new ministers basic instructions on staffing." 

LISTEN ABOVE AS MIKE WILLIAMS SPEAKS WITH MIKE HOSKING