The National Party has hit out at New Zealand First leader Winson Peters' lawsuit against two top public servants, saying he's putting personal vendettas ahead of the country.
Mr Peters lodged papers in the High Court in Auckland yesterday seeking $400,000 over the leaking of details of his superannuation overpayment.
Among the targets are Ministry of Social Development (MSD) chief executive Brendan Boyle and State Services Commissioner Peter Hughes.
He's also pursuing the Attorney-General David Parker on behalf of MSD and former National ministers Paula Bennett and Anne Tolley.
Mr Peters refused to answer any questions about the legal action at Parliament on Tuesday, saying any comment would amount to sub judice.
"You're infringing the sub judice rule now," he told reporters. "If you want that in front of the court, carry on.
"But you're not - any of you - going to be allowed the license to breach the sub judice law. That's not how our justice system works."
The term sub judice means "under judgment". The fundamental rule states that a person can be punished for publishing material which could prevent a fair trial.
National Party leader Simon Bridges said it was a strange and misguided move from Mr Peters.
"His very first act is to sue his own government and the most senior civil servant in the land," he said.
"He should be focused on doing a good job for New Zealanders, not on his own personal vendettas."
Prime Minister Jacinda Ardern earlier told Morning Report the lawsuit was a private matter.
"[Mr Peters] took this up before even becoming deputy Prime Minister. It is a matter for him as an individual," she said.
"In the last eight months in which he has held his political role, it has not affected his ability to do his job, nor do I expect it will in the future."
Ms Ardern said Mr Peters would recuse himself if any conflicts of interest arose in his Cabinet duties including if the targets applied for their legal fees to be paid.
"That is commonsense. That is the way the Cabinet manual operates."
It was revealed during last year's election campaign that Mr Peters had been mistakenly overpaid superannuation for seven years.
He paid the money back when the error was discovered, but was furious the information was leaked to the media.