Graham McCready files police complaint against Labour's Meka Whaitiri

Labour's Meha Whaitiri when sworn in as Customs Minister.

Serial litigant Graham McCready has filed a formal complaint of assault with police relating to the issues which led to Labour MP Meka Whaitiri being stood down as a minister.

In documents emailed to media and police today, McCready told police if it didn't investigate then he would take a private prosecution "against the Hon Meka Whaitiri without further delay or notice".

McCready's complaint stated: "The alleged offender became engaged with the alleged victim and subsequently pushed the alleged victim."

The basis of McCready's knowledge appears to be a media report attached to the complaint. He claims the assault happened on a specific date at Parliament but provides no material to support the claim.

Whaitiri was stood down as a minister over what was described as a "staffing matter" while an employment investigation took place.

It has since been reported that a staff member who had recently joined Whaitiri's office as press secretary had been pushed during a heated argument.

Whaitiri was known to have had a number of staff pass through her office since being appointed Customs Minister.

McCready has taken successful court action against politicians in the past.

He brought the prosecution against former Act MP and government minister John Banks over his electoral donations, which led to a conviction being overturned on appeal.

He was also behind the 2007 case in which Labour's Trevor Mallard was convicted of assaulting National's Tau Henare.

His complaint to police also copies in the Prime Minister, who is referred to in the documents as " Lucinda Ardern".

McCready is a former bankrupt who has a number of convictions himself - one for trading while bankrupt, for making false tax returns and for blackmail.

Whaitiri's Customs portfolio has been passed to Kris Faafoi during the employment investigation.

She has also lost her agriculture, local government and Crown/Māori relations associate portfolios.

Whaitiri was the second minister to lose her roles in a week. Clare Curran was earlier demoted from Cabinet.

A police spokesperson confirmed a complaint had been received and was being considered.