A number of countries, among them Bolivia, frequently stage home international games at high altitude but Blatter said FIFA was following advice from its medical committee.

"I know there will be complaints about this, especially from South America, but we have to think of the health of the players first,” he explained.

“It also leads to a distortion of the competition if matches are played at such a level.

"The Executive Committee have listened to a proposal from the medical committee and have decided to act because to play at above that altitude is not healthy or fair."

Bolivia traditionally play their home matches in La Paz, which, at more than 3,600 metres above sea level, is the highest capital city in the world.

He also said that the associations of Macedonia and Kazakhstan had been given a deadline of June 15 to resolve their internal problems or else face possible sanctions from world football's governing body.

He said FIFA would not relax its rules on shirt advertising for international teams and reported that of 23,000 doping tests carried out by FIFA in 2006, 91 had proved positive and of those just seven were for steroids.

"Most of the others were for marijuana or other things players use -- they were not even performance-enhancing," said Blatter, adding that FIFA would be using doping controls at all its major tournaments this year including the Under-17 and Under-20 World Cup matches in South Korea and Canada respectively.

He said he was delighted that 750,000 tickets had already been sold for the Under-20 World Cup in Canada from June 30.