Former Howard government minister Mal Brough says he has nothing to be ashamed of over his involvement in a failed sexual harassment case against former speaker Peter Slipper.

The Federal Court dismissed the case in December, declaring it to be an abuse of process and designed to further the political interests of Mr Brough and the Liberal National Party (LNP).

It emerged during the court proceedings that Mr Brough had requested extracts of Mr Slipper's diary from the staff member who ultimately filed the sexual harassment case, James Ashby.

Mr Brough has been preselected as the LNP's candidate for Mr Slipper's Sunshine Coast electorate of Fisher but has refused repeated requests for an interview until today.

Asked whether he thought it was wrong or illegal to obtain parts of Mr Slipper's diary, Mr Brough replied: "Mr Slipper's now about to face court next week and be charged ... on criminal offences relating to allegations of misuse of travel [entitlements].

"I think that's the right and proper place for such matters to be decided, so it would be entirely wrong of me to make any comment whatsoever about such issues."

Justice Steven Rares ruled that Mr Ashby had "acted in combination" with fellow staffer Karen Doane and Mr Brough when commencing the legal proceedings.

Mr Ashby has sought leave to appeal against the court's ruling, which is due to be heard in Sydney tomorrow morning.

Mr Brough insists the sum total of his involvement in the matter has already been fully canvassed and is on the public record.

"There is nothing more to add. There is no other meetings, connections or whatever else," he told ABC News.

"All of the discussion, the text messages - of which there is about half a dozen at most - are all there for anyone to read.

"I have nothing to be ashamed of or would change.

"A person (James Ashby) came to me for assistance. I suggested that they go and get legal advice. I suggested they go to police if they believed a crime had been committed.

"And that is the sum total of my involvement."

When pressed about the court's finding that he and Mr Ashby had worked "in combination", Mr Brough said he was not party to the court action and was not being judged.

Opposition Leader Tony Abbott has expressed full confidence in Mr Brough's behaviour and said he looked forward to his former colleague re-entering the parliament.

Labor has described Justice Rares's findings as "damning" and questioned Mr Brough's suitability to be a candidate.