The Australian Federal Police has dropped its investigation into the alleged copying of former Speaker Peter Slipper's diary.

Charges won't be laid against Mr Slipper's former staffer James Ashby - now an adviser to One Nation leader Pauline Hanson - or retired Liberal MP Mal Brough, who was alleged to have asked for a copy of the diary.

Police in November raided the homes of Mr Brough and Mr Ashby.

In a brief statement, an AFP spokesman said the matter was now finalised.

The AFP received a request in September, 2014 to investigate alleged unauthorised disclosure of information from Mr Slipper's official diary.

Following a thorough investigation, the AFP referred the case to the Commonwealth Director of Public Prosecutions who chose to take no further action.

"The length of this investigation has been influenced by a number of factors, including, but not limited to the availability of individuals to provide statements, the provision of materials from third parties, and the substantial volume of material that needed to be assessed," the AFP statement said.

In a tweet, Mr Slipper, 66, said he hadn't commented to the media and wouldn't be doing so.

"I've been put thru hell over the last few years. I just want 2 get on with my life," he tweeted.

"I would like to thank everyone 4 their support during this ongoing nightmare! It wouldn't have been possible to continue without it.

"Karma has a way of working things out."

Leaked extracts from Mr Slipper's diary led to a police investigation for misuse of travel entitlements and his conviction in the ACT Magistrates Court in 2014.

On appeal, the convictions were quashed.