The Pinnacle Midlands Health Network says it's not aware of what hackers planned to do with stolen patient information that had now been posted online.
The names, addresses and other personal information of up to 450,000 people has been posted online by cyber criminals.
The information was stolen in the hack of Pinnacle Midlands Health Network, which covers the Waikato, Taranaki and Tairawhiti areas.
CERT NZ monitors these types of cyber attacks, its manager of incident response Jordan Heerspring spoke to Kim Hill.