An ASX-listed company has been hit by a cyber attack just weeks after telecommunications giant Optus was breached.
Health insurance giant Medibank Group is the latest Australian company to become the target of a cyber attack.
Last month telecommuncations company Optus was hit by a wide-scale breach which saw more than two million customers affected.
Telstra was also rocked by a data breach which saw the personal details of 30,000 current and former staff leaked.
In a statement released on Thursday, Medibank said it had “detected unusual activity” in its network on Wednesday.
It said there is no evidence however that sensitive customer data had been accessed and that some of its systems have been taken offline.
The company has also requested a trading halt on the Australian Stock Exchange.
“As part of our response to this incident, Medibank will be isolating and removing access to some customer-facing systems to reduce the likelihood of damage to systems or data loss,” the statement said.
“As a result our ahm and international student policy management systems have been taken offline. We expect these systems to be offline for most of the day.
“This will cause regrettable disruptions for some of our customers.”
Medibank Chief Executive David Koczkar issued an apology and said the insurer’s highest priority is resolving the matter as “transparently and quickly as possible”.
“We will continue to take decisive action to protect Medibank Group customers and our people,” he said.
“We recognise the significant responsibility we have to the people who rely on us to look after their health and wellbeing and whose data we hold.
“We are working around the clock to understand the full nature of the incident, and any additional impact this incident may have on our customers, our people and our broader ecosystem.”
In the wake of the Optus breach, the telco said 2.1 million of its nearly 10 million customers had one form of identification targeted in the attack.
It is believed that 900,000 of them are expired documents.
Optus also revealed upwards of 50,000 Medicare cards and 150,000 passports had been breached.
Following the breach, the major telco has announced financial services company Deloitte will conduct an external review of the attack.
Medibank said there is nothing that customers need to do at this stage but customers can call on 13 23 31 for updates and further information.