The commission confirmed last year that it executed two search warrants with assistance from the Australian Federal Police and NSW Police on June 5 “in relation to an ongoing investigation”.

“As the matter is ongoing, the commission will not be making further comment, as to do so may compromise operational activities or unfairly impact reputations,” it said in a statement at the time.

A spokesperson for the NACC said on Monday: “It is inappropriate for the commission to comment on proceedings that are before the court.”

Lehrmann and Farrell were contacted for comment.

The court challenge against the NACC is the latest case involving Lehrmann, who has appealed against his damning Federal Court defamation loss.

Lehrmann has asked the Full Court of the Federal Court to overturn a finding by Justice Michael Lee that he raped his then-colleague Brittany Higgins in 2019 in Reynolds’ Parliament House office.

Burrows said in submissions to the Full Court last month that her client’s failed defamation case was a “quasi-criminal trial” and the presiding judge had insufficient evidence to find the former federal Liberal staffer was a rapist.

In his decision last year, Lee was satisfied Network Ten and journalist Lisa Wilkinson had proven to the civil standard – on the balance of probabilities – that Lehrmann raped Higgins. Lehrmann has always maintained his innocence.

Burrows said in written submissions filed in the defamation appeal that “where the evidence is inadequate, it may simply not be possible to judge the likelihood that something happened reliably enough to reach a rational conclusion one way or the other on the balance of probabilities”.