A computer science expert hopes Waikato DHB's cyber security woes are fixed by tomorrow.

The District Health Board's IT service is down after a major cyber incident, affecting all clinical services and forcing patient appointments to be cancelled.

AUT professor, Dave Parry, told Heather du Plessis-Allan it appears to be a ransomware attack.

“What they do is, basically encrypt the files that so you can’t access them easily, and then say ‘we’ll give you the passwords, effectively, for these so that you are able to use them again, if you give us this money.'”

Dave Parry says New Zealand doesn't normally pay ransoms, and the DHB can restore systems from backups.

He says that takes time, but he'd be surprised if it's more than a day.

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