Julian Assange has reached a deal with the United States Justice Department to allow him to return to Australia after pleading guilty to violating American espionage law.

A whistleblower authority is needed who will finally ensure these protections work fully, in practice, to best serve the public interest.

Sparked by the PwC scandal, the measures will expand tax promoter penalty laws to make it easier for the Australian Taxation Office to apply them to advisers and firms who promote tax avoidance.