Mr Jones has alleged that former Labor deputy chief minister David Lamont contacted Mr Costello and ActewAGL sponsorship manager Paul Walshe in February asking them to contact the Brumbies board members to complain about Mr Jones.

Mr Jones outlined the allegations in an amended statement of claim filed in the ACT Supreme Court as part of his case against the University of Canberra, its vice-chancellor, Stephen Parker, the UC union, rugby great Joe Roff, and Mr Lamont.

Mr Jones is alleging the five defendants pressured the Brumbies board to stand him down for blowing the whistle on financial irregularities with the sale of the club's former Griffith headquarters, and its subsequent move to Bruce.

On Tuesday, Mr Costello and Mr Walshe described the claims as "completely false".

"Mr Lamont never contacted either of us in February, or at any other time, in relation to speaking with Brumbies board members to complain about Mr Jones," the pair said in a statement. "The claims made by Mr Jones are simply not true."

The Brumbies board stood Mr Jones down in March following an explosive interview on ABC Radio in which he let fly at his critics in and out of the club.

He swiftly took the matter to court and used the ACT's whistleblower protections in an attempt to save his job.

Mr Jones argued the Brumbies were disciplining him for making disclosures over the sale of land in Griffith.

His case against the rugby club ended when he agreed to a payout and to mutually part ways this month. But the case against the University of Canberra and the other defendants remains before the Supreme Court.

Mr Jones is seeking to force them to pay damages.