Some surgeries have been cancelled at Eastern Health facilities in Victoria, following a "cyber incident" experienced late Tuesday.
Eastern Health operates the Angliss, Box Hill, Healesville, and Maroondah hospitals, and has many more facilities under management.
In a statement, Eastern Health said it took many of its systems offline in response to the incident.
"Many Eastern Health IT systems have been taken off-line as a precaution while we seek to understand and rectify the situation," it said.
"It is important to note, patient safety has not been compromised."
Eastern Health said Category 1 Elective Surgery will continue as planned, however, the incident has impacted its ability to undertake less urgent -- Category 2 and 3 -- Elective Procedures.
Data breach notification to the Office of the Australian Information Commissioner became mandatory under the Notifiable Data Breaches (NDB) scheme in February 2018.
Since the mandate, health has been the most affected sector. The latest NDB report shows no change, with health accounting for 123 of the total 519 notifications in the six months to December 2020.
Need to disclose a breach? Read this: Notifiable Data Breaches scheme: Getting ready to disclose a data breach in Australia
Health Minister says vaccine booking system 'glitches' were just day one rush
The federal government's COVID-19 vaccine booking service was on Wednesday inundated with people trying to secure their dose, with the Department of Health's eligibility tool suffering "problems".
According to Minister for Health Greg Hunt, day one was always going to be busy.
"The eligibility checker had approximately 243,000 people on health.gov.au, check their eligibility. We had a 98% connection rate, on the advice that we've received from the booking engine. And then what happens is that you approach your GP, in the vast majority of cases. Some take online bookings, some take telephone booking," Hunt said, when asked why the website was not working as expected.
"And in addition to that, the Commonwealth vaccination clinics will link through directly from the vaccination information and location service. So yesterday, 98% connection, 243,000 people who checked, 9,000 who actually registered for Phase 2, which is well beyond where we are now. And so what we've seen is a high uptake.
"And day one was always going to see a significant initial demand and I'm very pleased about that."
Due to the overload, and the fact phase 1b affects many people over the age of 70, the 1,069 GP's listed as receiving the vaccine were inundated with phone calls.
"This is a system that should have been in place well before the commencement, particularly, of phase 1b of the vaccine rollout strategy. Already, we are seeing widespread confusion and widespread frustration," health and aged care shadow minister Mark Butler said.
"The health system website continues to drop out, people are continuing to have problems logging onto a website that is the gateway to the vaccine rollout strategy.
"These systems should have been tested and finalised weeks ago. Instead all we are seeing out there today is chaos and confusion."
HealthEngine was selected by the federal government to build its COVID-19 vaccination booking platform.
It was reported by The Guardian that day one was actually meant to be Monday and that the medical appointment booking industry had been told to prepare their platforms to feed into HealthDirect, and for their client GP clinics to be trained with the software, by March 22.
"We've known for months that we would need a national booking system … more than 6 million Australians are due to be able to book their vaccines from next week without a National Booking System," Butler added. "This is utterly remarkable and irresponsible.
"This vaccine rollout is fast becoming a complete mess. It is way behind schedule and the systems that we need in place are still remarkably still being built."
Almost a year ago to the day, the federal government's myGov portal went down after thousands flocked to the website to sign up for income assistance following forced business closures in the wake of the coronavirus outbreak.
The minister in charge of government services Stuart Robert said the portal suffered a distributed denial of service (DDoS) attack while simultaneously blaming the outage on legitimate traffic that pushed past the 55,000 concurrent users limit set by government.
Those words were barely two hours old when Robert stood up in Parliament to say it was merely 95,000 people trying to connect to myGov that had triggered a DDoS alert, and not an attack at all.