Police move to final stages of Ashby case

The Australian Federal Police will head to court on Thursday to seek access to text messages as part of its investigation into the copying of former Speaker Peter Slipper's diary.

The AFP applied in April to the Federal Court to use evidence from an earlier civil case in a potential criminal prosecution.

The evidence includes mobile phone messages between Mr Slipper's former staffer James Ashby and former coalition MP Mal Brough.

AFP commissioner Andrew Colvin told a Senate estimates hearing in Canberra last week the majority of the investigation was now complete.

"However, there are still a couple of significant avenues of inquiry that we are following", he said, one of which was the Federal Court application.

Police have executed search warrants on the Department of Parliamentary Services to obtain records held on computers, as well as at the homes of Mr Ashby and Mr Brough.

The search warrant on Mr Brough's home mentioned two other ministers, Wyatt Roy and Christopher Pyne.

Mr Ashby launched a sexual harassment suit against his boss in 2012.

The court heard Mr Ashby made copies of Mr Slipper's diary, which were sent to Mr Brough and the then News Limited journalist Steve Lewis.

A newspaper story series about Mr Slipper's use of government-issued taxi vouchers led to him losing his seat of Fisher to Mr Brough at the 2013 election.

The AFP has asked the Federal Court to grant use of the material from Mr Ashby's phone, including excerpts from Mr Slipper's diary sent by Mr Ashby to Mr Brough.

Mr Ashby's harassment case was rejected by a Federal Court judge, who said the staffer had been part of a "combination" including Mr Brough, using court action to pursue a political attack.

Mr Ashby appealed and the original judgment was set aside, but he later dropped the case.

Mr Brough stood aside from the frontbench in December and in February decided not to recontest his seat.

The AFP search warrant, tabled in parliament, says police are investigating whether Mr Brough "counselled and procured" Mr Ashby to disclose extracts from Mr Slipper's official diary and provide those extracts to third parties without authority.