The High Court has granted an order preventing anyone from accessing, sharing or publishing coronial files obtained from a cyber attack last month.
There was no clear evidence of any unauthorised access or downloading of the material, but it could not be ruled out.
Te Whatu Ora and the Ministry of Justice yesterday jointly filed proceedings in the High Court to prevent people accessing or using the files.
In a joint statement, they said it was a proactive step to protect private and sensitive information.
"Te Whatu Ora and the Ministry of Justice - Te Tāhū o te Ture can confirm that they have jointly filed legal proceedings in the High Court today to prevent people accessing, sharing or publishing confidential and sensitive coronial and health information at the centre of a recent cyber security incident," the statement said.
"The National Cyber Security Centre, Police and CERT NZ are investigating the incident. We are also working with the Privacy Commissioner."
The order was granted following an urgent High Court hearing yesterday.
There was an existing precedent for obtaining orders against unknown people.
Te Whatu Ora and the Ministry of Justice said the legal action was not designed to constrain media reporting of the incident, but to protect the people whose information had been compromised.
Earlier this month, the Ministry of Justice and Te Whatu Ora said access to data held by external IT provider Mercury IT had been blocked and multiple agencies were assessing the extent of the problem.
Access to 14,500 coronial files and about 4000 post-mortem reports from around the country were affected.
The coronial files related to the transportation of people who have died during the period of November 2018 to November 2022.
The ministry said post-mortem data related to files from the Northland, Waikato, Bay of Plenty, Taranaki, Wellington, Horowhenua-Kāpiti, Nelson-Marlborough, Otago and Southland regions from March 2020 to November 2022.
About 8500 records for bereavement care services at Auckland's Middlemore Hospital and about 5500 files on the Cardiac and Inherited Disease Registry were also impacted.
The Privacy Commissioner's office said it was notified of the attack on 30 November.
In their statement yesterday, Te Whatu Ora and the Ministry of Justice acknowledged the anxiety the cyber attack had caused to those affected.
Anyone who thinks they might be affected can contact the ministry via email firstname.lastname@example.org or by calling 0800 638 924.