Tony Nutt, a former chief-of-staff to John Howard when he was prime minister, denies covering up allegations of sexual misconduct made against Peter Slipper in 2003 and says he may have been defamed in media reporting of the controversy.
Mr Nutt's name was mentioned in Federal Court documents which allege a formal complaint was made to him about the conduct of Mr Slipper with a staffer in 2003.
Mr Nutt said in a statement on Monday he was "seriously concerned about false reports" of the matter in the media.
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"I have legal advice from a leading defamation expert that confirms they are highly defamatory," he said.
"The matter is currently before the Federal Court, so it would not be appropriate for me to make further comment at this time except to note that in the Statement of Claim filed in the Federal Court (now in wide public circulation) the final two lines of paragraph 9 (page 3) state that the person concerned `formed the view that the relationship was consensual'."
Mr Nutt now works for Victorian Premier Ted Baillieu.
Mr Slipper, the former Liberal turned independent MP, stood aside as Speaker pending a possible criminal probe into allegations he misused taxpayer-funded Cabcharge vouchers.
He also faces the civil claims - to be heard by the Federal Court next month - that he sexually harassed a former male aide. He strenuously denies all the allegations.
As part of the criminal case against Mr Slipper, the complainant in the matter, James Ashby, plans to give a statement to Australian Federal Police about three alleged incidents relating to the alleged misuse of public funds.
He alleges Mr Slipper gave a three signed government Cabcharge vouchers to a "friend" who picked the pair up at the airport during a trip to Sydney on January 27.
Mr Ashby is seeking compensation, civil penalties against Mr Slipper and the Commonwealth and an order that Mr Slipper undergo anti-discrimination counselling and training.
Mr Slipper, the independent MP for Fisher, became Speaker on November 24, 2011.
