World Anti-Doping Agency president Craig Reedie says the absence of an accredited doping laboratory at the World Cup in Brazil in June will not affect drug testing.
Samples taken at the World Cup will need to be flown across the Atlantic to Switzerland, raising doubts that positive tests from players will be discovered before their next matches.
Reedie, who is also an International Olympic Committee vice-president, called it "rather disappointing" that the new laboratory will be ready for the Olympic Games in 2016 but won't be ready for the World Cup.
But Reedie has tried to quash doubts that samples would not be tested in time in Brazil.
He says FIFA can do it because in football there's about a four or five-day gap between matches so the turnover of samples in Lausanne can be done quickly enough so that the process will work.
WADA said in August the Rio de Janeiro laboratory did not meet the International Standard for Laboratories.