Patients on elective surgery waiting lists in Waikato can expect more delays the longer a cyber attack on the region's public hospitals takes to resolve.
A ransomware attack on Tuesday crashed all the district health board's computer system and it is likely to be out of action this coming week and maybe beyond that.
During the week 80 percent of around 1500 elective surgeries a day went ahead, leaving hundreds now back on the waiting list.
Eighty percent of outpatient clinics have also gone ahead.
DHB chief executive Kevin Snee said planning is now underway for when services resume in full.
''And we will be clearly wanting to put a lot of resource, both to re-enter the written date and to make sure patients have their treatment if it has been deferred and if that means using other partner hospitals or using the private sector, then we will do that.''
Snee said it is likely to mean extra elective surgery will take place to help catch up.
He said the cyber security crisis facing his organisation will in time become a case study on how to deal with a similar event.
Snee said there will be many lessons to be learned from the attack.
''Clearly it's happening in many organisations across the world and it's very difficult to protect against, but there are things that we can do. We have done what we thought we needed to do. I am sure we can always do more and will learn the lessons from it.''
Snee said it is too early to be giving advice to other DHBs or public sector organisations.
He said the DHB deploys a range of cyber defence capabilities to help protect its network.
''I am not going to comment on the nature of those services, or who they are provided by. We have an ongoing investigation into the cause of this incident and I am not going to speculate on that at this time.''