Waikato DHB chief executive Kevin Snee said today it had examined the data sent to media by hackers and it appeared to be genuine. The DHB was working closely with privacy experts.
They would be contacting those affected individuals within the next few days and providing support to them which could include counselling or guidance.
The DHB was working through the files that were leaked and would then look at the support those individuals needed.
The DHB hadn't been in touch with them yet, but would soon.
"Given there's a concern out there we want to be getting in touch with people and looking at what wider communications we can give to the wider public to make sure people are aware of the problem."
He was not aware of the hackers sending the files anywhere else.
Substantial progress was being made to its IT system, Snee said.
"We are expecting to make very significant progress over the next few days." He expected to make an announcement on this within the next few days.
Snee said the Covid vaccination programme was coping well despite the cyber attack and the DHB was 10 per cent ahead of its rollout target.
Snee said there was "quite a number" of extra IT experts working with them as they faced a massive task - including restoring 680 servers.
Getting cancer services back online were a priority for the IT team.
"The longer this goes on for, the longer this recovery period will be. My guess is the recovery period will be longer than the event itself."
Government agencies were providing good support to the DHB, including the ability to transfer patients to other hospitals for treatment, based on the merits of each patient.
As well as cancer treatment, the DHB was also looking at outsourcing complex orthopaedic surgeries to local private hospitals.
Waikato DHB hospital and community services executive director Chris Lowry said its manual processes were still in use as it carried out acute and elective surgeries and outpatient clinics.
There were 294 presentations to its emergency departments across all sites in the past 24 hours - just slightly lower than normal.
There had been 125 elective surgeries at Waikato and Thames hospitals in the past 24 hours and seven surgeries had been deferred. A further 1800 clinical appointments had also been carried out.
Cancer Control Agency chief executive Diana Sarfati wanted to reassure patients they were working hard to ensure their treatment would continue with the least amount of disruption as possible.
She acknowledged it was an unwanted disruption for patients at what was already a very stressful time.
The 73 patients who had been receiving radiotherapy when the system went down were now receiving treatment, or would be shortly, in Wellington and Tauranga.
"At this stage we are aiming for all patients disrupted by this event to be treated in New Zealand."
Sarfati said they were confident they had identified almost all the relevant cancer patients.
There was a plan being put together to manage the radiotherapy patients on waiting lists at the other cancer centres around New Zealand.
"All options are being looked at right across New Zealand."
Sarfati said she did not think the prospect of travelling to Australia would be appealing to patients at this time and it was her strong recommendation that treatment be done in New Zealand.
Cancer services escalated to national response
Radiotherapy and oncology had been escalated to a national response and the Cancer Control Agency was assisting with help on the ground.
The DHB has also been urged by the Privacy Commissioner John Edwards to contact immediately patients whose files were sent to media by the hackers to prove they had stolen the documents.
"We would also expect that the DHB would be actively monitoring for potential host sites on the Dark Web or elsewhere."
While his office was not investigating to determine any liability at this stage he has shot a warning to all DHBs to make sure they adequate security.
The Commissioner also said he was aware of the leaked information sent to media outlets, saying it expected the DHB to notify and offer support to the individuals identified in that information without delay.
Health Minister Andrew Little confirmed the DHB had been provided at least some of the documents sent to media by the hackers and also wanted it to make contact with those people affected.
On Monday night people claiming to be the hackers contacted media outlets saying they had given the Waikato DHB one more day to respond.
The group claiming responsibility for the attack claimed it had accessed confidential patient notes, staff details and financial information.
They said the DHB had until Tuesday to comply with its demands or warned the information would be made public. That deadline has now expired.
Snee would not comment on the details of the cyber attack over fears the "malicious actors" would be monitoring communications.
