"No further activity [has been] seen within the last 24 hours."
"The WDHB runs up-to-date operating systems with antivirus and malware protection," he said.
"We are reviewing security procedures to strengthen existing controls."
Earlier this week, a Los Angeles hospital hit by ransomware was forced to pay off the hackers targeting its network.
The Guardian reported Hollywood Presbyterian Medical Center lost access to its computer systems since February 5 after hackers installed a virus that encrypted their computer files.
The hospital paid the hackers $17,000 in bitcoin to regain access to the files.
A PwC New Zealand survey of concerns held by chief executives showed a big growth in concern around cybersecurity and data security sector.