Medibank hack accessed all customer data

They're working through each individual customer so each person knows what information the hackers accessed.

"We believe that the scale of stolen customer data will be greater and we expect that the number of affected customers could grow substantially," Medibank chief executive David Koczkar said.

"I apologise unreservedly to our customers. This is a terrible crime – this is a crime designed to cause maximum harm to the most vulnerable members of our community."

Medibank has announced a support package for those affected that includes financial backing and specialist identity protection.