The information technology systems at a number of hospitals and health services in Gippsland and south-west Victoria, including Latrobe Regional Hospital in Traralgon, have been impacted by a cyber security incident.
According to the State Government, at this time, there is no suggestion that personal patient information has been accessed.
A statement issued by the Department of Premier and Cabinet said a number of servers across the state had been impacted and investigations were still taking place on the full extent of the impact.
"The Victorian Cyber Incident Response Service has been deployed and worked with impacted health services overnight to respond to the attack," the statement read.
The cyber incident, which was uncovered on Monday, blocked access to several systems including financial management.
Hospitals have isolated and disconnected a number of systems such as internet to quarantine the infection.
"The priority is to fix all affected systems and prevent any further compromise.
"This isolation has led to the shutdown of some patient record, booking and management systems, which may impact on patient contact and scheduling."
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.