Seven Olympic athletes from Cameroon who sparked speculation they were seeking asylum after they left their official residence in the athletes village have valid visas to stay in Britain for the next six months, the spokesman for Cameroon's Olympic team says.

The athletes have freedom of movement, Emmanuel Tataw told The Associated Press on Wednesday, though he acknowledged that in similar cases athletes from Cameroon have not returned to their home country because they are seeking better training opportunities abroad.

"This is not the first time it happens. It has happened in Melbourne and Athens," he said, referring to earlier Olympic Games. "Most of the time they don't come back."

Tataw said the athletes left the Olympic village in Stratford, east London, in the middle of the night "without the authorization of Cameroon authorities."

The missing athletes include five boxers, a swimmer and a soccer player. London Olympic officials said Cameroon's Olympic delegation is seeking help finding them, but made clear that the athletes had not breached their visas.

"The team has obviously raised a concern and the police are obviously informed," International Olympic Committee spokesman Mark Adams said. "But at this stage I don't think it's necessarily for the IOC to worry about whether they will outstay their welcome."