Millions of Australians may have had data accessed by hackers after Origin Energy confirmed it is investigating a cybersecurity incident.

The energy giant is aware of an incident where unauthorised access to customer data may have been granted, it said in a statement to the ASX on Wednesday.

However, the company said it did not believe the data that was breached included customer credit card or bank details.

“We understand an incident like this may raise concerns and acknowledge the impact of this uncertainty on Origin customers,” it said.

“Our investigations into this incident are occurring as a matter of urgency, and Origin will provide further updates as appropriate.”

Origin provides electricity, natural gas, LPG and internet services to residential and business customers. It has 4.8 million customer accounts in Australia.

The company said it had notified the federal police, the Australian Cyber Security Centre and the Office of the Australian Information Commissioner about the incident.

Shares in the company had dropped nearly 3 per cent from the open at 1.30pm.

-AAP