The Argentinian Football Association (AFA) announced their squad, to play in the same group as the Olyroos, at the beginning of July and included the forward.

However, the Games clash with the dates of the Champions League preliminary round and Barca have insisted they will do everything in their power to hold onto the 21-year-old.

But the International Olympic Committee (IOC) and FIFA have threatened to ban Messi from playing football for the duration of the Games, should the Catalan club fail to release him.

"FIFA have just reminded clubs that they must release their players," IOC president Jacques Rogge told Spain's Sport newspaper.

"The law indicates that if a team don't release a player, the footballer will be suspended during the period of the Games.

"That means that if the player doesn't go to Beijing, he won't be able to play for his club."

This has further narrowed Barca's already slim chances of preventing Messi from playing in Beijing.

Messi has said he wants to represent his country, while FIFA have reiterated that their rules stipulate players under the age of 23 must be released by their clubs for the Olympics.