Claims by National Anti-Corruption Commission boss Paul Brereton that he “recused” himself from the Robodebt referrals have “no justification whatsoever” and are “simply wrong", says top former judge.

An investigation has been launched into the National Anti-Corruption Commission over its refusal to investigate referrals from the Robodebt Royal Commission.

Attorney-General Mark Dreyfus used fudged data to justify implementing the almost entirely secret National Anti-Corruption Commission, vastly understating the amount of NSW anti-corruption hearings held in public.