'Major incident' declared as police investigate NSW Health cyber breach

Police are investigating a major cyber security breach at NSW Health, but officials have reassured the public that patient data has not been compromised.

About 1pm on Friday, the State Crime Command's Cybercrime Squad was alerted to a suspected data breach at NSW Health.

Cyber Security NSW, which leads the state government's response to significant cyber incidents and cyber crises, said the breach had affected an isolated server.

"The breach has been declared a major incident," a spokesperson said.

NSW Health directed media inquiries to NSW Police.

In a statement, NSW Police said cybercrime squad detectives were leading the investigation under Strike Force Civic and were working closely with NSW Health and Cyber Security NSW.

Transport Minister John Graham told 702 ABC Sydney the incident was a "big reminder about the importance of cyber security".

"It is getting more difficult, there's no question about that," he said.

"Whether you're in government or in a private company or just as a citizen, it is an increasingly difficult area."