And Italian lawyer Angelo Massoni and his team are studying Nakamura's Parkhead contract to determine whether there is an escape clause that will allow him to leave for around £1million.

Massoni told the Scottish Daily Mail: "I have spoken with [Nakamura's agent] Roberto Takudo about this and we want to meet with Celtic next week.

"We have four of the biggest clubs in world football interested in Nakamura and willing to pay big money. We will recommend these offers to Celtic.

"Obviously, if Celtic want to make a better offer, that is up to the club.

"We cannot name the clubs interested from the other countries until we have informed the club first."

Nakamura last year signed an extension to his contract with the Scottish Premier League champions, which could keep him in Glasgow until 2009.

But reports claim he is unhappy at earning considerably less than the likes of Thomas Gravesen, who struggled to hold down a first-team place last season.

Meanwhile, Gravesen's agent John Sivebaek revealed Turkish side Besiktas had made an inquiry about the former Real Madrid midfielder, but said the Dane wanted to remain with Celtic.