The Mandatory NDB Scheme requires all organisations that meet the criteria specified by the government to report any IT breach to the Office of the Australian Information Commissioner (OAIC). More information can be obtained on the following link.
https://www.oaic.gov.au/privacy-law/privacy-act/notifiable-data-breaches-scheme
Ethical Security can assist you in ensuring your organisation meets all the criteria set by the OAIC and implementation of preventative measures to ensure your organisation is not vulnerable