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Large data breaches

Steps to make sure your personal information is safe if it has been lost or stolen in a data breach or cyber incident.

Last updated 24 August 2023

Optus data breach

We're aware of the recent Optus data breach and that people who have been affected might be concerned about their personal information.

We want to assure you that ATO systems have not been affected by the Optus data breach.

If you think you've been affected by the Optus data breachExternal Link, phone Optus Customer Service on 13 39 37.

Medibank cyber incident

We understand that the Medibank private cyber incidentExternal Link is stressful for those people affected.

If you think you may be affected by the recent Medibank private cyber incident:

Information for affected customers

We're aware of the potential fraud and identity theft risks with taxpayers’ personal information being compromised.

Information for customers affected by large data breaches:

The ATO takes data security seriously and we have several safeguards and systems in place to protect taxpayers.

Reminders for the community

It's important to always be vigilant for suspicious activity.

These tips can help protect your accounts and keep your personal information safe:

  • Use multi-factor authentication for your accounts where possible.
  • Be careful when clicking on links and providing personal information.
  • Make sure your contact details are up to date when using online services.

Other websites that can help you protect yourself and stay informed:


If you would like to make a privacy complaint, contact OptusExternal Link or Medibank PrivateExternal Link. If you are unable to resolve your complaint directly, you can lodge a complaint with the Telecommunications Industry OmbudsmanExternal Link or the Office of the Australian Information CommissionerExternal Link.