Fifa will conduct a review of Olympic football regulations to ensure the London Games in 2012 are not hit by more club-versus-country rows.

Barcelona, Werder Bremen and Schalke have appealed to the Court of Arbitration for Sport (CAS) in a bid to stop the likes of Argentina midfielder Lionel Messi from competing at the Beijing Olympics.

Fifa insist clubs must release their Under-23 players for international duty based on a regulation passed by the congress in 1988. It has never before been an issue.

Fifa president Sepp Blatter today urged the clubs to "let the players play" -but he admitted an urgent review was required.

"In the future I think it is necessary we have an exact and precise ruling," Blatter said. "It has been decided for 2012 to avoid any misunderstandings and problems — plus or not plus three overage players — that the whole item of the presence of football in the Olympic Games shall be discussed immediately after the conclusion of the 2008 Olympic Games, together with the IOC.

"The discussion will be open and is (designed) to have a clear and clean situation for everybody for the 2012 Olympics which will be played in London."

Fifa will present their case to CAS tonight and Blatter expects a final ruling within the next 48 hours.

"It is not only a question of solidarity. It is also a question of respect to the Olympic spirit to let the young players have the experience," he said.

"Jurgen Klinsmann wrote in his book: 'The moment I received the bronze medal in the Olympics in Seoul 1988 when Germany beat Italy it was my number one outstanding emotion'.

"We need the leagues and the clubs but we need players. Even if the ruling is negative for the players they should stay here, they should play here."

The Fifa and IOC review could see an end to the current rule which allows each country to select three players over the age of 23rd.

Fifa last discussed the possibility of turning the Olympic football tournament into an Under-23 competition back in 2006 but congress decided to retain the three over-age players for the Beijing Games.