Three-quarters of elective surgery planned for Waikato Hospital today will go ahead as the DHB continues to deal with a crash of its IT system following a cyber attack.
The Waikato District Health Board (DHB) said of 102 elective surgeries for inpatients scheduled, 73 would happen.
On Tuesday it said 95 operations were carried out and six were cancelled.
The number of outpatient clinics at Waikato Hospital today has been reduced.
Elective surgeries have been postponed at Thames Hospital and all outpatient clinics at Thames along with Te Kuiti, Tokoroa and Taumaranui hospitals have been deferred.
The DHB said IT staff worked through the night to get the system back online and were making good progress.
However, it said it was a complex process, and would take longer to resolve.
The DHB said a forensic examination was ongoing into how the attack happened and it was working on the theory the incursion was via an email attachment.
It said staff were working to restore the infected systems and on a remediation process.
Anyone with queries about the urgency of their outpatient appointment should contact their GP.
Health Minister Andrew Little said Waikato DHB was getting all of the assistance requested, including help from the National Cyber Security Centre within the GCSB.
Little said New Zealand's health IT infrastructure was fragmented and overly complicated and that connecting and upgrading health IT systems was a key objective of the government's health system reforms.
Serious breach
The Privacy Commissioner is awaiting further information to determine if it needs to investigate any breach of confidential information following the cyber attack.
A spokesperson for the commissioner said the Waikato DHB had formally notified the office of the incident, as required under the Privacy Act 2020.
This means the cyber attack has reached the threshold of a serious breach.
"Notification does not automatically prompt an investigation by our office. We are monitoring the situation and will rely on further updates from the DHB," the spokesperson said.
They said the Office of the Privacy Commissioner had not received any complaints from individuals.
If individuals think they are harmed by this breach, they can lodge a complaint.
"However, at this stage, it would be premature to assume harm had resulted to individuals, although we recognise (and I'm sure the DHB does too) that there is a real potential for harm to eventuate from this breach."
DHBs nationwide on alert
The country's other DHBs are on high alert too.
In the Wellington region, the Wairarapa, Hutt Valley and Capital and Coast DHBs share a technology service, and have temporarily blocked all traffic with the Waikato DHB.
A spokesperson said it has reminded staff to be vigilant for cyber attacks and scams, and it continued to monitor systems and the wider situation.