Origin Energy (ASX:ORG) said it contacted about 900,000 current and former customers after their information was subject to unauthorized access, according to a Friday Australian bourse filing.

The company said it has confirmed the specific types of information accessed on a customer-by-customer basis and is well advanced in providing further specific notifications, including details of the information accessed and advice on practical steps customers can take.

For a smaller subset of customers, some additional information was accessed, including full bank account numbers for about 60 customers in total, the filing added.

Origin said it has taken steps to enhance the security of its systems with the support of external cybersecurity and forensic specialists, with the incident remaining subject to an ongoing criminal investigation and the company continuing to work closely with the Australian government and the Australian Cyber Security Center, among other agencies.

The company's shares rose 1% in recent Friday trade.