Just over six months since Optus reported a major hack, a class action is being lodged on behalf of customers who say their safety has been compromised.
Law firm Slater and Gordon has lodged the class action in the Federal Court on behalf of more than 100,000 registered participants.
The lawsuit claims Optus breached consumer and telecommunications law and failed in its duty of care to protect users from harm.
"We have people who work in frontline occupations — police officers — very, very concerned that criminals will find out where they live," the firm's Ben Hardwick said.
"So the the release of this information causes people great anxiety. It causes them great concern.
"And, so, this class action is about seeking redress for the potentially millions of Australians who have been affected by this data breach."
An Optus spokesperson said the company had noted filing of a class action by Slater and Gordon and would vigorously defend any such proceedings.
Around 10 million current and former Optus customers had personal details stolen in the hack, which the telecommunications giant revealed in September last year.
Mr Hardwick said the lawsuit would be seeking a "substantial" compensation sum on behalf of those current and former customers.
Former customer Kate— who is part of the class action and asked not to be identified — said she had experienced domestic violence in the past.
"The release of this data has potentially breached the safety of me and my children," she said.
"I've spent every day basically anxious, just wondering if my details were going to fall into the wrong hands."
She said she would like to see "accountability and responsibility" as well as acknowledgement of the deep distress caused by the data breach.
"It's not just something that just was an inconvenience then and there. It's something that's continuous and ongoing for the victims," she said.
Lawsuit comes after class action taken against Medibank
Optus came under fire from the federal government in the aftermath of last year's attack, which Home Affairs Minister Clare O'Neil claimed was a "basic" effort by cyber criminals.
The company strenuously denied human error was a factor in the attack, which is being investigated by the Australian Federal Police, the information commissioner and ACMA, the communications watchdog.
Optus apologised for the breach and set aside $140 million to help customers renew ID documents and commission an independent report into the breach.
It has also promised to invest more in protecting its systems and rebuilding customer trust.
The lawsuit is not the only class action related to high-profile customer data breaches.
Earlier this year, three law firms launched a case against Medibank after a breach that affected around 9.7 million customers.
