Melbourne, Oct 1 (IANS): Hospitals in Australia's Victoria state were infiltrated by "sophisticated cyber criminals", forcing the cancellation of surgeries and the shutdown of computer services, authorities said on Tuesday.

Targeting the Gippsland Health Alliance and the South West Alliance of Rural Health, the Victorian 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."

"Where practical, hospitals are reverting to manual systems to maintain their services," Xinhua news agency quoted the statement as saying.

Affecting operations at Warrnambool, Colac, Geelong, Warragul, Sale, and Bairnsdale and a number of other smaller regional towns, "the Victorian Cyber Incident Response Service has been deployed and worked with impacted health services overnight to respond to the attack", it said.

Expected to take "up to weeks" to secure the network, hospitals have gone offline in an attempt to quarantine the infection and protect patient data.

"This isolation has led to the shutdown of some patient records, booking and management systems, which may impact on patient contact and scheduling," the statement said.

"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."