Barcelona president Josep Maria Bartomeu has denounced FIFA for punishing the La Liga club over a breach of rules on the transfer of foreign under-18 players, calling it a "grave injustice".

Soccer's world governing body announced on Wednesday it had banned the Spanish champion from the transfer market for two consecutive windows and fined it $504,700.

The Spanish soccer federation (RFEF) was fined $564,000 after FIFA found it had also breached rules on the transfer of minors.

Barca denied wrongdoing and said it will move to get the transfer ban suspended until its appeal is heard, and vowed to take the case to the Court of Arbitration for Sport if necessary.

Bartomeu fiercely defended the Catalan club's La Masia academy, which has produced the likes of Lionel Messi, Xavi and Andres Iniesta, at a news conference on Thursday.

He said Barca will push ahead with plans to buy at least a goalkeeper and a central defender during the offseason.

"We are outraged and the victims of a grave injustice," Bartomeu said.

"With this sanction, FIFA is punishing a model that has existed for 35 years and which is the essence of this club.

"FIFA knows that we do things well and we look after the children and give them an education that perhaps they wouldn't get in their own country.

"We are not prepared in any way to give up our educational model. We have defended, continue to defend and will always defend the rights of minors.

"Hands off La Masia, that's the message we want to send to our members and fans - hands off La Masia!

"We will fight until the end to protect this model because it has made our first team a leader in world football.

"We have absolute confidence in our lawyers and they tell us we have good grounds to think that the sanction will be lifted."

FIFA's punishment was the latest blow to the club and came after Bartomeu's predecessor, Sandro Rosell, was forced to step down in January amid allegations of misappropriation of funds and tax fraud linked to the signing of Brazil forward Neymar.

Rosell has always denied any wrongdoing.

Argentina forward Messi and his father have also been implicated in a tax fraud probe and Bartomeu suggested there might be a concerted campaign to damage the club.

He said it was "very strange" the FIFA decision to sanction Barca, which he noted came after an "anonymous denunciation", had been taken at the end of November but not communicated to the club until more than four months later.

"We have noticed for quite a while now that someone is trying to damage Barca and we are investigating," he said. "We have suffered many things these past years and we are suffering this now."

Bartomeu was repeatedly asked who would want to damage the club, including if it might be arch rival Real Madrid, but he declined to provide any names.

Barca has 18 players from outside Spain currently training at the La Masia academy, including seven from Cameroon, three from Guinea-Bissau, two from Morocco, two from South Korea and one each from Nigeria, Senegal, France and Germany.