Deputy Prime Minister Winston Peters fails in privacy claim against Paula Bennett, Anne Tolley and others

Deputy Prime Minister Winston Peters' privacy claim over a leak of his pension details has failed because he could not identify who was responsible.

A high court judgment released this afternoon said that Peters' privacy was deliberately breached in the lead-up to the 2017 general election to publicly embarrass him and cause him harm.

But the New Zealand First leader's claim against former Government ministers Paula Bennett, Anne Tolley and others failed because he was "not able to establish that they were responsible for the disclosure of the payment irregularity to the media".

For that reason, Justice Geoffrey Venning ruled that his claim for damages and a declaration that his privacy had been breached was dismissed.

On top of the declaration, Peters had sought $1.8m in damages from Bennett, Tolley, former Ministry of Social Development chief executive Brendan Boyle, State Services Commissioner Peter Hughes, and the Ministry of Social Development.

The court found that in the event he was successful in his claim, damages would have been far lower -"in the region of $75,000 to $100,000 might have been appropriate". Costs in the case were reserved.

Peters said the case had caused "considerable stress" but he was pleased the judge had recognised it was a breach of his privacy.

"Every New Zealand citizen is entitled to their privacy. This case has caused considerable stress.

"It is seriously welcome to see that Justice Venning confirmed that this was a deliberate and malicious breach of privacy done with the intent to damage my reputation and cause harm."

He said it was always going to be difficult to prove who had leaked it.

"While we are disappointed we could not prove who deliberately leaked that data, the ruling makes clear MSD contributed to the error. We hope that MSD reflect on their role in this matter. As the holder of extraordinary amounts of individuals data, it is paramount they take appropriate steps to safeguard New Zealanders' privacy."

Bennett and Tolley said in a joint statement that they were pleased with the court's decision, "as the judge has said our evidence was accepted and unchallenged".

"We do not think the claims against us should have been made when there was no evidence to support them," they said.

"It is a pity it was necessary for taxpayers to bear the financial burden of these court proceedings."

Bennett and Tolley both had their legal costs covered by the Government. The Crown's costs in the case were more than $500,000.

In May 2017, the Ministry of Social Development discovered that Peters had been wrongly paid the single person's pension for seven years despite being in a long-term relationship with partner Jan Trotman. Once alerted, he paid back the $18,000 difference and MSD decided not to open a fraud case.

National Party politicians Paula Bennett, right, and Anne Tolley (centre, in blue) arriving in court in November. Bennett and Tolley both denied leaking Peters' pension details. Photo / Peter Meecham

Boyle alerted the State Services Commission, and Tolley and Bennett were briefed in their social development and state services portfolios under the "no surprises" convention.

The details of the overpayment made its way into media in August 2017, a month before the general election in which Peters was likely to play a key role.

Peters took legal action before he started negotiating with the National Party about a potential coalition after the 2017 election.

A two-week hearing was held in November, in which Peters and the ministers appeared in the witness box.

Venning said in his decision that Peters had a reasonable expectation that the details of the overpayment would be kept private.

"In particular, he had a reasonable expectation that the details of the payment irregularity would not be disclosed to the media.

"The deliberate disclosure of the details of the payment irregularity to the media would be regarded as highly offensive to an objective reasonable person."

However, Peters had conceded that neither Bennett nor Tolley were directly responsible for the disclosure to media.

"Further, with the exception of the very general, unguarded comment by Ms Tolley to her sister, the disclosures by [Bennett] and [Tolley] were for a proper purpose or otherwise to persons with a genuine interest in knowing."

While appearing in the witness box, Tolley admitted that she had told her sister about Peters pension overpayment after her sister had praised him.

"I sincerely regret my outburst with my sister. I was tired and I was cross," she said at the time.

But she said she was not responsible for the information making its way into the media. Bennett also denied being the source of the leak.

Disclosures by Boyle and Hughes under the no surprises policy were also "for a proper purpose" and to ministers who had "a genuine interest in knowing the details of the payment irregularity", the ruling said.

During the hearing, MSD and the Crown argued that Peters was responsible for the mispayments.

Justice Venning, however, said the error arose through a combination of circumstances.

"The ambiguous nature of the form, the MSD officer who processed Mr Peters' application and Mr Peters himself all bear some responsibility for the error which led to the payment irregularity."