The cooling issue has now been resolved and services are in the process of being restored.
Te Whatu Ora confirmed there was no external cause or influence contributing to the outage.
“Hospital services continue to see patients for outpatient appointments and planned care and procedures – however patients may experience delays due to our systems currently running more slowly than usual.
“Should a patient need to be deferred, they will be rescheduled at the next available opportunity. All decisions about deferrals are made on a case-by-case basis by clinical teams, however teams are working hard to try to ensure that deferrals are kept to a minimum.”
Anyone needing emergency or urgent care would continue to receive it, and anyone unsure of whether they needed urgent care should contact their GP or medical centre, it said. People could also call Healthline on 0800 611 116 for advice.
People experiencing emergencies should still call 111.