Peterborough United are in dispute with Crystal Palace over the sell-on fee due following the sale of striker Dwight Gayle to Newcastle United.
Palace sold Gayle to Newcastle for £10 million last week, and reports have claimed that the League One club were entitled to more than £1million due to a sell-on clause.
Gayle was sold to Palace for £6 million three years ago and the Peterborough attached sell-on and additional payment clauses.
Barry Fry, the club's director of football, said: “Palace have never bought the clause out. It is still in place and we are currently arguing with them over the amount due to us."