Staff from at least two ministerial offices have been quizzed about leaks linked to raids on the Australian Workers Union.
The Australian Federal Police is also spreading its net to several agencies, including itself, as it investigates whether government information was disclosed without authorisation ahead of the 24 October raids.
"We're looking at the whole timeline of who had what information and when, including the AFP," Deputy Commissioner Leanne Close told a Senate inquiry on Tuesday.
AFP officers executed the warrants in Sydney and Melbourne after the Registered Organisations Commission flagged fears documents were being tampered with or destroyed.
The raids drew scrutiny after the media arrived at the AWU's offices before police, thanks to a tip-off from the media adviser to Employment Minister Michaelia Cash. The staffer quit in the wake of the scandal.
Senior AFP officers said they were surprised to see media at the AWU raids and began an investigation of their own volition the following day.
AFP Commissioner Andrew Colvin said while the AWU raids were fairly routine operations, media tip-offs could potentially put officers in danger and compromise operations.
The potential offence the AFP is investigating carries a maximum of two years in jail.
The AFP has received 50 allegations of unauthorised disclosures of government information since July 2013, with roughly 30 investigations ongoing.
The force is confident its investigation into the AWU raids will be wrapped up fairly soon but admits it is not a top priority.
