Optus customers involved in the data breach are entitled to a free Equifax subscription

The credit reporting agency Equifax was itself the victim of a significant cyberattack in 2017 when up to 143 million US citizens' data was breached.

Equifax general manager, consumer, James Forbes, said the organisation has invested in robust cybersecurity since then.

"In the six years since that occurred we have transformed our security and we do have one of the highest security ratings in the world. We've invested globally about 1.5 billion USD in new security and technology capabilities."

Stolen identities may be used to take out loans or other products in your name, so taking out a credit report is an important step to monitor any credit fraud. Equifax will send alerts to all Optus customers who take up the free subscription if an account is opened in their name.

The service also includes an identity watch feature that will monitor the dark web for personal details such as bank details or drivers licenses and alert you if they are being traded.

Mr Forbes said that victims of identity theft may see a negative impact on their credit score.

"A fraudulent account opened in your name won't necessarily impact your credit score, but the inability to repay that facility that's been opened up in your name...then that becomes a tricky situation," he said.

"It could indirectly lead to an impact on your credit score."

Optus customers will also be entitled to compensation of up to $15,000 to help restore a stolen identity, including cover for legal or court costs and lost wages.

Optus announced this week that Deloitte has been commissioned to conduct a forensic review of the cyberattack and the circumstances surrounding it. The results of the independent review will not be shared publicly.

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