Authorities have scrambled to respond after Victorian hospital computer networks were hacked in a ransomware attack.

The government insists patient information is safe after it was revealed that hospitals in the Gippsland Health Alliance and of the South West Alliance of Rural Health were attacked.

“The Victorian Cyber Incident Response Service has been deployed and worked with impacted health services overnight to respond to the attack,” the Department of Premier and Cabinet said in a statement.

“The cyber incident, which was uncovered on Monday, has blocked access to several systems by the infiltration of ransomware, including financial management.”

Servers across the state were hit and investigations to reveal the extent of the intrusion are still underway, but the government says “at this time there is no suggestion that personal patient information has been accessed”.

Hospitals have isolated and disconnected a number of systems in order to quarantine the infection.

“This isolation has led to the shutdown of some patient record, booking and management systems, which may impact on patient contact and scheduling,” the statement says.

“Where practical, hospitals are reverting to manual systems to maintain their services.

“The affected hospitals are now working on their bookings and scheduling to minimise impact on patients, but may need to reschedule some services where they don't have computer access to patient histories, charts, images and other information.”