N'Diefi was part of the Cameroon national team squad at the 2002 FIFA World Cup and the 2004 African Cup of Nations, as well as at the victorious 2000 and 2002 African Cup of Nations. He also scored the winner in the infamous 2003 FIFA Confederations Cup semi-final between Cameroon and Colombia, where teammate Marc-Vivien Foé died on the pitch.