Fordham has made a number of baseless assertions
The Northampton Saints and Wallaby back Cameron Shepherd are heading for a stand-off that could end in an ugly court battle.
Shepherd said this week he is taking legal action against the English club, the Saints, after they terminated his contract for medical reasons.
Saints on Thursday hit back at the player and his agent, Nick Fordham, saying they are spreading lies.
Shepherd, who has joined with rival English club Sale Sharks, was due to join the Saints on a three-year deal this month after seven seasons with Super Rugby team the Western Force.
Northampton cancelled the contract just days before Shepherd was due to join the club on grounds that he failed a medical - due to the condition of his left ankle.
Shepherd's Australian-based agent, Fordham, said in a statement he was "appalled at the behaviour of Northampton in respect of the manner in which his client and family were treated".
"Expert medical reports from leading independent orthopedic surgeons and Cameron's former doctors at the Western Force have concluded that there is nothing wrong with Cameron's ankle," he said.
"Having subsequently passed a medical and signed with the Sale Sharks proves there are huge holes all through Northampton's action and position".
Fordham said Shepherd was only advised by Northampton of the medical results three days before his departure for the England - and a month after he undertook the medical.
Northampton Director of Rugby Jim Mallinder last week defended the club's decision to withdraw Shepherd's contract.
"We obviously monitored Cameron's condition between signing his contract and his scheduled arrival and, after great consideration, felt that on balance we needed more certainty about his ability to handle the tough demands of our long season for the duration of his three-year contract," Mallinder said.
Shepherd has been troubled by groin and wrist injuries and played just two games for the Force in 2012.
He made his Super rugby debut with the Waratahs in 2004 and played nine Tests for Australia between 2006 and 2010.
The Saints on Thursday released a statement in response to Fordham's revelation that they to take legal action against the club.
"Northampton Saints strongly refutes the allegations made by Nick Fordham, Cameron Shepherd's agent, on Wednesday, August 15," the statement said.
"Fordham has made a number of baseless assertions on the events surrounding Cameron Shepherd signing a deal with Northampton Saints and the club's subsequent decision not to proceed with the contract, something which the club believes it was well within its rights to do.
"Northampton Saints had been prepared to sign Shepherd, who when fit is a talented player, on a generous three-year contract. Once terms had been agreed, the club flew lead physiotherapist, Matt Lee, to Melbourne to conduct the player's medical.
"During this medical, material information about Shepherd's left ankle came to light, about which the club had not been aware during the contract negotiation process.
"The player's ankle joint was scanned and the results sent to one of the UK's leading ankle specialists. Relying on his expert opinion, the club concluded that it was unlikely that Shepherd would be able to contribute fully to the club's squad throughout the three-year term, and decided not to proceed with the contract.
"It should be noted that while Shepherd has subsequently signed for Sale, it has been widely reported that this is for one year and not three, with the Sharks' Director of Rugby Bryan Redpath commenting: 'We're hoping to get him fully fit'.
"After the medical, Shepherd's agents in the UK and Australia were kept fully informed of the club's concerns. While the final decision regarding Shepherd's contract was made shortly before the player left Australia on a long holiday prior to his scheduled arrival in the UK, the club's initial concerns were raised several weeks beforehand.
"It is the club's standard practice to communicate with agents regarding contractual issues, with Jim Mallinder and other members of rugby management talking to and emailing Shepherd's representatives regularly throughout the process; there was also direct communication with the player from Mallinder (contrary to the claim made by Fordham).
"The Northampton Saints management is in particular surprised to note that Fordham, with whom the club has had no dealings prior to the termination of the Shepherd deal, has taken it upon himself to question the integrity of what is regarded as one of the best run Premiership clubs.
"Although the Northampton Saints management feel it necessary to make this statement to refute Fordham's allegations, the club does not anticipate making any further comment until the matter has been concluded. The club will vigorously defend any legal proceedings which are served."