The cyber attack on Waikato DHB is "probably the most significant attack that we've had in New Zealand on any organisation", according to the Ministry of Health's Deputy Director-General of Data and Digital Shayne Hunter.
Hunter says malware attacks are increasing and no organisation is immune.
"Cyber criminals are criminals, they're very creative and they will continue to look for ways to find access to data. It's a game of cat and mouse, to be frank, so everything we do is an attempt to stay ahead of them."
Health Minister Andrew Little visited staff and patients at cyber-stricken Waikato Hospital today and said they're coping.
"The hospital is at roughly 85 percent occupancy, that's pretty standard. They are getting through procedures that are still being carried out on sight here, people are going up to ED and getting the treatment that they need - they've kept it ticking over in these extraordinary circumstances."
The DHB says progress is being made as it works to rebuild its IT systems.
"We're hoping to have our radiotherapy service up and running by the middle of the week", said DHB Chief Executive Kevin Snee.
While staff are still relying on pens and paper, they're due to install new electronic devices at the weekend, with hopes of having a first system in place at the end of next week.
A number of patients and staff have had their data leaked, just how many hasn't been revealed but those affected will be contacted from today and through next week.
Other DHBs have been asked to look at their IT systems and provide assurances that they're resilient to such cyber attacks.
