Waikato DHB bosses are continuing to put contingency plans in plan for deal with patients as work to fix its broken IT system continues.

The Waikato DHB is mainly largely on manual processes after a serious and significant cyber attack locked staff out of its system last Tuesday.

Hundreds of appointments and surgeries have been deferred as a result and some seriously sick or cancer patients are being sent to other hospitals around the country for treatment.

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 and providing support to them.

Substantial progress was being made to its IT system, Snee said.

"We are expecting to make very significant progress over the next few days."

Waikato DHB hospital and community services executive director Chris Lowry said its manual processes were still in use.

There were 294 presentations to its emergency departments in the past 24 hours - just slightly lower than normal.

There had been 125 elective surgeries in the past 24 hours and 7 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.

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.

Waikato DHB is holding daily press conferences.