The Australian Signals Directorate got drawn into the Christchurch shooter investigation immediately after the attack, and is working closely with New Zealand authorities and ASIO to help unravel what lay behind it, the organisation has revealed.

Mike Burgess, director-general of the Australian Signals Directorate. Credit: Ben Rushton

Mike Burgess, who heads the normally highly secretive ASD, brought his organisation “out of the shadows” on Wednesday, with an address to the Lowy Institute in Sydney and a round of media interviews.

He said that as soon as the shooter was "deemed a threat to security” Friday week ago, ASD sought and gained ministerial authorisation to help with the Christchurch investigation.

But he rejected suggestions Australian authorities had taken their eye off right-wing extremism because of an overly narrow focus on radical Islamic-inspired terror.