Charlton Athletic say a "ridiculous" High Court insolvency action against the club will be "vigorously defended".
The Sun reports former executive chairman Matt Southall is claiming a seven-figure fee for services during his time at the club.
Southall joined in January when East Street Investments took over, but he was removed from the board in March.
"We are aware of Mr Southall’s alleged claim, which we feel is entirely misplaced," said lawyer Chris Farnell.
Southall fell out with Tahnoon Nimer, a fellow former co-owner of ESI, over proposed investment into the club shortly after the pair bought Charlton from previous owner Roland Duchatelet at the start of the year.
Despite being removed from his position at The Valley, Southall remained a minority shareholder in ESI.
However, businessman Paul Elliott completed his buy-out of ESI from Nimer and Southall on Tuesday, becoming chairman of the south-east London outfit.
The Sun reports Southall registered a complaint against Charlton on 5 June, and that his Sports Investment Group will have their case reviewed in the business and property courts on 14 December.
"It is our intention to bring proceedings against Mr Southall and others arising out of his short tenure at the club," Farnell added in a statement on the club website.
“In the recent past too much has been played out in public, which is not professional and unfair on the Charlton fans, and with this in mind the club will not make any further statements on this matter.”