Thousands of patients who used a South Australian home hospital service have been caught up in the Medibank cyber attack.
The South Australian government agency Wellbeing SA said about 4,400 patients have had their personal and some medical information accessed in the recent Medibank data breach.
They were part of the My Home Hospital program, which treats people with less-serious conditions in their homes.
It is jointly run by Medibank and the not-for-profit healthcare organisation Calvary on behalf of the state government.
Medibank has apologised and says it will contact patients directly.
At least 4 million Medibank customers across Australia have also had their data potentially accessed and stolen by the hackers.
My Home Hospital was launched in January last year, with the aim of reducing ambulance ramping and overcrowding at hospitals.
It initially serviced only the Adelaide metropolitan area but was expanded to include Gawler, Mallala, Two Wells and Freeling last July.
Wellbeing SA chief executive Lyn Dean said Medibank had previously advised the My Home Hospital program was not caught up in the data breach, but revised that information on Wednesday night.
"All of the patients impacted by the data breach are being contacted by Medibank to inform them of the situation and what actions they can take," she said.
"My Home Hospital patients who accessed the service for the first time on or after October 13 are not impacted by the breach.
"My Home Hospital patients are the only SA Health patients aligned with Medibank and, therefore, the only ones who could have been affected."
Ms Dean said personal information such as names, addresses, date of births and the reason for admission were accessed, but stressed that medical records had not been breached.
"The data has been accessed, but they do not know whether at this point the data has been stolen," Ms Dean said on Friday morning.
"So it may well been that it's been opened and seen and closed, and no further action, and they have been working through this every day to really determine that."
Medibank has set up a hotline for My Home Hospital patients at 1800 081 245.
"We are quite disappointed and really feel for those 4,400 patients," Ms Dean said.
