New details of embattled Labour MP Meka Whaitiri's track record with staff have surfaced today.
They come the day after Ms Whaitiri stood down as Customs Minister over what 1 NEWS understands is an allegation of assault on a staff member levelled against her.
Ms Whaitiri is a protege of former Labour Minister Parekura Horomia.
A source close to Mr Horomia's office told 1 NEWS that during the time Ms Whaitiri worked as a senior private secretary, she allegedly used threatening behaviour to staff and then Prime Minister Helen Clark's office was forced to step in.
Ministerial services are undertaking the investigation but there's no date yet on when it will be completed.