FIFA say any player taking part in the proposed breakaway European Super League would be blocked from playing at major international tournaments - including the World Cup.
Outgoing Barcelona president Josep María Bartomeu announced in October that the Catalan giants had agreed to participated in a new 18 club pan-European competition, which would not be controlled by European's governing body UEFA.
Real Madrid and Juventus are also strongly speculated to be among the major clubs in favour of joining the tournament, though reigning Champions League winners Bayern Munich have this week poured cold water on their potential involvement.
The fresh reports have led to FIFA making a statement this morning in conjunction with the six confederations, opposing the creation of a European Super League.
"In light of recent media speculation about the creation of a closed European “Super League” by some European clubs, FIFA and the six confederations (AFC, CAF, Concacaf, CONMEBOL, OFC and UEFA) once again would like to reiterate and strongly emphasize that such a competition would not be recognised by either FIFA or the respective confederation.
"Any club or player involved in such a competition would as a consequence not be allowed to participate in any competition organised by FIFA or their respective confederation.
As per the FIFA and confederations statutes, all competitions should be organised or recognised by the relevant body at their respective level, by FIFA at the global level and by the confederations at the continental level.
"In this respect, the confederations recognise the FIFA Club World Cup, in its current and new format, as the only worldwide club competition while FIFA recognises the club competitions organised by the confederations as the only club continental competitions."