Acting Australian Information Commissioner Timothy Pilgrim has launched an investigation into the release of confidential data from AshleyMadison.com.
A hacking group dubbed Team Impact last month claimed it had obtained access to a large volume of data from Ashley Madison, a service for people seeking extramarital affairs.
After Ashley Madison owner Avid Life Media ignored the group's demand to shut down the service, Team Impact release an 8.68GB database dump, which included the personal details of people who had signed up for the service.
A second 18.5GB dump was released several days later and contained more data including source code and company emails.
Pilgrim, who in October is due to reprise his role as Privacy Commissioner, said the OAIC investigation would be conducted jointly with the Office of the Privacy Commissioner of Canada.
"Avid Life Media has already been co-operating with the OAIC since it began making preliminary inquiries following news that the breach had occurred," an OAIC statement said.
"The OAIC will publish a further statement at the conclusion of its investigation, outlining its findings."