Mal Brough says Peter Slipper's diary notes sent to him by James Ashby in a text message were 'unsolicited'.

FEDERAL Police will today make a court application that could lead to Malcolm Turnbull’s election campaign being derailed close to polling day.

The AFP will ask the Federal Court for access to records related to the James Ashby affair — the claim that a former staffer to Peter Slipper copied his employer’s confidential diary and gave the information to others.

This comes as Mr Turnbull was linked to a company named in the Panama Papers. He was a former director of a company incorporated by embattled law firm Mossack Fonseca, but there is no suggestion Mr Turnbull had acted improperly.

Federal Police Commissioner Andrew Colvin has revealed that investigations into the most enduring controversy of recent federal political history are close to conclusion.

“What I will say is that the majority of the investigation has been completed. However, there are still a couple of significant avenues of inquiry that we are following,” Commissioner Colvin told a Senate Estimates committee last week.

On April 27, the AFP was granted approval for a Federal Court application for the records.

“It involves records held by the Federal Court from a different process, a different hearing that the Federal Court was involved in,” Mr Colvin said.

If the investigations lead to charges being laid in the next seven weeks, Mr Turnbull could have to carry the campaign burden of prominent Liberals — past and present MPs — having to explain their actions.

And the pressure would be only slightly less were a former MP linked to a campaign to undermine Mr Slipper in reprisal for his move from the Liberals to help the minority Labor government.

James Ashby worked for Mr Slipper, the Liberal who turned independent, when Julia Gillard offered to promote him from deputy speaker to speaker in late 2011.

He was in the post for less than 12 months and left amid controversy over his relationship with Mr Ashby, and allegations he had misused allowances.

Mr Ashby, who has been working recently as a pilot for perennial candidate Pauline Hanson, took a sexual harassment case against Mr Slipper. He did not succeed, but the action resulted in damaging text messages and emails being released.

Former Liberal minister Mal Brough, who has publicly acknowledged receiving a copy of the Slipper diary from Mr Ashby, is not standing again for his seat of Fisher, formerly held by Mr Slipper.

Police interviewed Mr Brough in January.

Mr Ashby has suggested sitting MPs — Industry Minister Christopher Pyne and Assistant Minister for Innovation Wyatt Roy — might have been involved in the anti-Slipper operation. There has been no evidence to support this and the pair have denied it.

“I know Mr Ashby has seen fit to talk about certain things in the media but I do not think it is appropriate for me to confirm or deny whether we have taken statements or whom we may be interested in,” Mr Colvin said.

In February, the AFP executed warrants to get “relevant material” from Parliament House computers.

“It related to records that (the Department of Parliamentary Services) hold,” Acting Deputy Commissioner Ian McCartney told the Senate committee.

The AFP officers made clear they would soon be in a position to lay charges.

“From our perspective, the majority of the investigation has been completed, but we need to go through and assure ourselves we have all of the relevant material before we make a final judgment,” Mr Colvin said.