The ombudsman has found former minister Stuart Nash was wrong not to release most of his emails with political donors, after receiving an official request.
Nash was stripped of all of his ministerial portfolios after it emerged he sent an email to senior business figures in 2020 which contained Cabinet discussions related to a commercial relief package being negotiated.
In 2021, a Newsroom journalist requested all of Nash's communications with his political donors under the Official Information Act, but the email that ended Nash's career was not released as Nash claimed he sent it as an MP - not as a minister.
The journalist later made a complaint to the Ombudsman, prompting an investigation.
Ombudsman Peter Boshier said 14 relevant emails and attachments were withheld, but only three were sent in Nash's capacity as MP for Napier.
Eleven emails were relevant to his role as a minister and most should have been released, Boshier said.
"However, I believe there were grounds under the OIA to withhold all of one email and parts of two emails because confidential Cabinet decisions were discussed."
"There is a strong public interest in release to promote accountability and transparency where a minister appears to have disregarded the confidentiality of Cabinet discussions. However, I consider the public interest in releasing them would not have outweighed the need to withhold the emails to protect collective and individual ministerial responsibility."
Boshier said he would have recommended at the time Nash send a summary of the emails to the journalist.
"A summary would have informed the public of the apparent breach of the minister's responsibilities without undermining the confidentiality of Cabinet discussions by the further release of the improperly disclosed material."
The case had highlighted the potential for ministers to hold information in their capacity as both an MP and minister, Boshier said.
"The Official Information Act is an important constitutional safeguard. It is based on the principle of making information available.
"In my view the OIA should apply where there is a ministerial overlap of any kind."
Boshier also investigated the role of former prime minister Jacinda Ardern's staff in the release of the emails.
Two of Ardern's senior staff were consulted about the journalist's official information request.
Boshier found the staff did not support Nash's position on refusal.
"Decision-making on the request rested at all times with Mr Nash, who it appeared did not agree with the advice provided by the prime minister's senior advisor, and proceeded to make the decision now at issue."