Despite Muntari moving to Inter from Fratton Park two years ago, the two clubs are still wrangling over the fee to be paid, with Portsmouth claiming they are owed a further sum approaching £900,000.
An extra party is involved in the fracas over the Ghana international, with Udinese claiming that Portsmouth owe them £450,000 as an additional payment for Muntari featuring in the 2008 FA Cup final and getting the club into Europe.
Pompey chief executive David Lampitt said: “We are owed €1m (£855,000) by Inter Milan because Muntari has made a certain number of appearances for them.
“We are chasing the money and so were the administrators and now we are calling in Fifa.”
Inter, however, claim to have bypassed Portsmouth and paid Udinese when it looked as if the Italian club were suffering from financial difficulties that may have put them out of business.Lampitt added: “At some stage, there has been an agreement between Udinese and Inter Milan, whereby Inter Milan appear to have assigned that €1m to Udinese.”