She said there have been no impacts from the cyber security attack.

"There are no cyber security related cancellations for any surgery and/or any other type of medical, dental, GP clinic, community health and mental health appointments," she said.

"We have set up a 24/7 hotline phone number for local people wanting assurances that Monday's cyber security incident has not affected upcoming appointments for any of our SWH patient services. That number is 5564 4253."

She said staff pay would not be impacted.

"We want our workforce and suppliers to know that while out business systems have been impacted, we are confident wages and invoices will be paid as normal.

"We still cannot send or receive emails."

At 8.45am: For Warrnambool Base Hospital today is business as usual, according to a spokeswoman.

She said all the Southwest Healthcare sites and campuses were functioning.

"There are no cancellations for any surgery and/or any other type of medical appointments," she said.

"Our Warrnambool emergency department and Camperdown urgent care centre are also operating as usual."

Questions have been asked about what is not working and whether staff are going to be paid this week.

The South West Alliance of Rural Health has been subject to a randomware attack.

The SWARH includes the Balmoral Bush Nursing Centre, Barwon Health, Barwon South Western Regional Integrated Cancer Centre, Casterton Memorial Hospital, Colac Area Health, Dartmoor Bush Nursing Centre, Hesse Rural Health Service, Heywood Rural Health, Lorne Community Hospital, Moyne Health Services, Otway Health & Community Services, Portland District Health, Southwest Healthcare (Warrnambool) Terang & Mortlake Health Services, Timboon Healthcare and Western District Health Services.

Earlier: One of Australia's top spy agencies is investigating a cyber attack that has sent south-wesat hospital networks into lockdown, delaying surgeries.

Hospitals that are a part of the South West Alliance of Rural Health - Warrnambool, Portland, Hamilton, Port Fairy and Colac - and Gippsland Health Alliance and have been targeted by ransomware.

The facilities have isolated and disconnected a number of systems to quarantine the infection, as federal and Victorian authorities investigate.

The team includes the Australian Cyber Security Centre, part of the secretive Signals Directorate, alongside Victoria and Federal Police.

"At this time, we have no information to indicate that patient data has been compromised," David Cullen, principal advisor to the Victorian government on cyber incidents said.

"This will be a long, complex and protracted forensic investigation."

Mr Cullen could not say if it would take weeks or months to get the systems running again and why the two hospital networks were targeted, but no other government departments had been harmed.

Premier Daniel Andrews confirmed elective surgeries and other procedures will be delayed as staff at the hospitals return to manual scheduling where possible.

Mr Cullen said the corporate networks of the hospitals were also hit, which could impact administrative functions such as staff pay.

The state government was warned in an auditor-general report released in May that cyber security at Victorian hospitals needed improvement.

A similar report in Queensland found government systems to be vulnerable to cyber attacks and international espionage.

Mr Andrews said the system "is much stronger than it's ever been" however "you can build a fortress, but if people are prepared to put the planning into it, there are still ways to get in".

Since launching 14 months ago, the Victorian Government Cyber Incident Response Service has responded to more than 600 cyber-attacks on state government organisations.

"Across the Victorian government, somebody tries to break into a computer system every 45 seconds and thankfully, we have a lot of great people, a lot of great controls and protections in place that stop those attacks from getting through," Mr Cullen said.

"But like any government, and like any big organisation, occasionally somebody will break in, that is the reality of our modern digital world."

University of Melbourne privacy and cyber security expert Suelette Dreyfus said hospitals across the world had been targeted by ransomware attacks because of the valuable information they hold.

An attack on Singapore's health network targeted the prime minister's records.

Dr Dreyfus said government at all levels needed to do more to warn institutions and the private sector of potential risks.

"There are certainly entities between the states and federal bodies that should be providing advice and support to the cyber security people within government departments, hospitals and the private sector," she said.

Such attacks serve as important reminders for people to maintain cyber security, including keeping software up-to-date, using password managers and two-factor authentication, Dr Dreyfus said.

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