Udinese contact CAS over Muntari
"We can confirm that we are presenting a case to CAS over the payment of Muntari's transfer," a spokesman for the Serie A club said on Thursday.
Ghanaian midfielder Muntari is now back in Serie A having joined champions Inter Milan in 2008 after only a season in England.
British media reported that Portsmouth still owe Udinese around four million pounds for the player. Muntari joined Portsmouth for around seven million pounds.
It is more bad news for the club, owned by Saudi businessman Ali al Faraj, who have had a miserable season on and off the pitch.
Currently bottom of the Premier League, they face a winding-up order over unpaid taxes, have been banned from any transfer activity and have three times failed to pay their players on time.
Former Portsmouth defender Sol Campbell said on Wednesday he was suing the club for fees and bonuses he said he was owed.
Last week the Premier League awarded seven million pounds of their television revenue payments to other clubs who were still owed transfer fees by Portsmouth.