Three Guineans and three Ivorians disappeared, adding to a total list of 11 Congolese and Cameroonians suspected to be trying to make new lives in Europe.
"Three members of the delegation have not returned to the Olympic village," Adama Doumbia, technical adviser at the Ministry of Sports and Leisure in Ivory Coast, said.
He did not give the names of the missing members of the delegation but said they contained two swimmers and a wrestling coach.
An official on Guinea's Olympic Committee said on condition of anonymity that swimmer Dede Camara, judo competitor Facinet Keita and runner Aicha Toure had been missing since Saturday, the day before the closing ceremony.
Games officials are already looking for a Democratic Republic of Congo judo competitor, three other members of that country's delegation and seven Cameroonian athletes.
The London Olympic organising committee said it had notified British police about the missing Cameroonians but added the athletes would not be infringing immigration laws until their visas expired in November.