Costa Rica's football federation has sent a letter to FIFA demanding an explanation for why so many of its players were required to submit to anti-doping controls after a surprise victory over Italy.

Seven Costa Rica players were tested after Friday's 1-0 win, angering team officials who say it could lead to people believing that football's world governing body suspects Costa Ricans of doping.

"We believe in, accept and trust doping controls that FIFA carries out, but we want an explanation as to why so many of the players were called in," said Adrian Gutierrez, the president of Costa Rica's selection committee. "What causes surprise at the world level is that they take seven players in one sitting for anti-doping tests, which gives an image of suspicion that Costa Rican players are doping."

According to the federation, FIFA said eight players weren't available for testing before the World Cup when a FIFA anti-doping commission visited Costa Rica as part of a routine control carried out on national teams competing in Brazil. Two of those players were tested after the Uruguay match and the other six were tested after the Italy match, the federation said on its website. A seventh Costa Rica player was chosen by lottery.

Coach Jorge Luis Pinto challenged FIFA to test all his players and even himself after Costa Rica's next match, which is against England on Tuesday in Belo Horizonte.

"I'm happy that they do these types of tests," he said. "If they want in the next match, they can test all 11 players on the pitch and even me."

FIFA says it's 'standard procedure'

The decision to test the seven Costa Rica players was standard procedure, soccer's governing body FIFA told Reuters.

FIFA spokeswoman said that two of the players were called for the post-match anti-doping tests as usual while the remaining five needed to be tested for their so-called biological passports.

More than 90 per cent of the players at the World Cup were tested for the biological passports before the tournament, while the remainder, including the five Costa Ricans, have to be tested during the competition, the spokeswoman said.

"This was standard procedure, there was nothing suspicious," she told a FIFA media briefing.