A European Super League is a realistic possibility if Champions League format changes are not altered, according to the EPFL.
UEFA has put the building blocks in place to eventually create a European Super League, according to European Professional Football Leagues (EPFL) chairman Lars-Christer Olsson.
The Champions League format is set for an overhaul from 2018, with the top four teams from each of the biggest four leagues afforded an automatic place in the group stage - a move seen as a bid to appease the biggest clubs and quell the threat of a breakaway.
The changes are yet to be ratified, but the proposals have been met by widespread criticism, with smaller clubs facing a tougher task to make an impact on the continental stage.
Olsson says the situation has come about partly as a result of a "vacuum of leadership" at UEFA in the wake of president Michel Platini's departure over ethics breaches, but he hopes new chief Aleksander Ceferin - a critic of the plans - can steer the governing body to a more palatable outcome.
"They have put all the building blocks together to get that [a European Super League] as the final result of the procedure," he told Omnisport.
"That is absolutely not acceptable. This is something we have to set for the future. It has nothing to do with the coming period from 2018 but what is coming after.
"I'm convinced that there will be a proper procedure before any major changes are made to the Champions League and Europa League."
Olssen offered a gloomy outlook for clubs from Europe's smaller leagues - the likes of Celtic, Ajax and Porto - should the proposals be adopted.
"If we can't change the decisions now, you should be very worried," he warned.
"It's not very promising for the smaller or mid-range clubs because what has been done is laying the foundation for a future private enterprise, which I think is totally against the ideas of European sport in general.
"The best thing for the fans to do is to support their associations and their clubs and to promote a proper development of European club football."
Neil Doncaster, chief executive of the Scottish Professional Football League, added that the major stakeholders of European football were united against the proposals, suggesting domestic fixtures could be arranged to clash with continental matches in response to any such changes.
"I've never seen - in 20 years within the game - clubs, leagues, associations, so many, so united against a set of proposals," he commented.
"It's rare indeed that you unite the vast majority of people within the game. UEFA have achieved that but not in a way that's supportive of the current proposals."