Australia's competition watchdog has launched Federal Court proceedings against Google, alleging the internet giant misled Australian consumers to obtain their consent to expand the amount of personal information about their internet activity it collected and combined.

The Australian Competition & Consumer Commission accuses Google of misleading consumers when it failed to properly inform them, and did not gain their explicit informed consent, about its move in 2016 to start combining personal information in consumers' Google accounts with information about those individuals' activities on non-Google sites that used Google technology, known as DoubleClick technology.

This meant that data about users' non-Google online activity became linked to their names and other identifying information held by Google, the ACCC said. Previously, this information had been kept separately from users' Google accounts, meaning the data was not linked to an individual user.