Optus chief executive Kelly Bayer Rosmarin has offered an emotional apology to customers for the company’s data breach.
It follows a colossal cyberattack affecting over nine million Optus customers.
"We have strong cyber security controls in place. We thwart… thousands of attacks every year, every day," she said.
"But it’s a good warning to all organisations that even if you have strong cyber capabilities, dedicated focus and investment in this area, there are sophisticated actors out there.
"We are working very closely with all the authorities and the Australian Federal Police. This is a criminal investigation."