The seven Olympians have valid U.K. visas that would allow them to stay in Britain for six months, press attaché Emmanuel Tataw told The Associated Press, noting this has happened before to national or Olympic squads competing in Melbourne and Athens.
"Most of the time they don't come back," he said.
Cameroon sent 37 athletes to the London games and more than half of them, mostly the women's soccer team, had left the city after they were eliminated. The missing athletes include five boxers, a swimmer and a soccer player, all of whom had completed their events, he said.
Cameroon, a predominantly French-speaking nation of 20 million in west central Africa, is among the poorest nations on earth, with an estimated 2011 economic output of just $1,230 per person, according to the International Monetary Fund.
Tataw said the five boxers also had Schengen visas because they had trained in Italy before the games. That would make it easier for them to travel legally to other European countries, including France, which has a large Cameroonian community that includes some athletes' friends and family.
London Olympic officials said even though Cameroon officials were seeking help in locating the athletes, they had not breached their visas or violated any immigration laws.
"The team has obviously raised a concern and the police are obviously informed," International Olympic Committee spokesman Mark Adams said Wednesday. "But at this stage I don't think it's necessarily for the IOC to worry about whether they will outstay their welcome."
Tataw said the boxers had refused to hand in their visas for safekeeping at the start of the London Olympics, which should have been seen as a "hint" that they wanted to leave. He said it is often financially beneficial for the athletes' families if they are able to find a niche in Europe.
Boxer Thomas Essomba, one of the missing, had earlier stayed in Britain after a Welsh championship rather than return to Cameroon but that didn't work out, Tataw said.
Government officials will meet after the games to come up with ways to stop this from happening in the future, he said.
"(But) it's a phenomenon that can't be stopped completely," he added.
He listed the seven as 50-meter freestyle swimmer Paul Edingue Ekane, 21; women's goalie Drusille Ngako Tchimi, 25; and five boxers: Essomba, 24; Christian Donfack Adjoufack, 28; Hyacinthe Mewoli Abdon, 26; Blaise Yepmou Mendouo, 27; and Serge Ambomo, 26.
Sports officials in Cameroon told the AP there were indications of problems with the boxing team. Jean Paul Monyemo, deputy national trainer for boxing, said head trainer Justin Tchouem told him on Friday the team might be planning to defect.
"But no one suspected they would move so fast. By Sunday morning, they had disappeared," he told the AP.
He said the dismal conditions in Cameroon can prompt athletes to seek new opportunities overseas.
"What generally pushes Cameroonian athletes to disappear in foreign countries is the kind of bad treatment they get at home," he said.
Britain's Office for National Statistics says fewer than 20,000 Cameroonians live in the UK.
The U.K. Border Agency says the majority of asylum applicants from Cameroon are refused and deported.
Associated Press writers Rob Harris and Sylvia Hui in London and Divine Ntaryike in Cameroon contributed to this report.