The European Club Association "do not think it is appropriate" that the continent's top players should be asked to play at the 2012 Olympics.
Debate is already raging about whether Great Britain will be represented at London 2012 by a cross-section of players from all four national home associations or just from England.
Now games organisers have another hurdle to overcome.
ECA vice-president Umberto Gandini feels the time scale between the two summer tournaments is too short to expect clubs to release elite players for both events.
"We do not think it is appropriate that European players will play in the European championship and then some of the same players will be involved in the Olympics in London a few weeks later," he said.
"It does not make sense for a club player to be involved in two major tournaments in such a short period of time. We have appealed to UEFA to say that if a player is selected for Euro 2012, he should not be selected for the Olympics.
"As the Olympics are not part of the international calendar we are going to face the same situation we did in 2008 where there will be requests for release of players where the clubs have other activities going on. We hope we can discuss this without getting into conflict as we did in 2008."
Manchester United chief executive David Gill, an ECA board member, agreed.
"A player who is in the squad for Euro 2012 should not then be in the Olympic squad," Gill said. "Football is a key part of the Olympics and we are very happy to participate as a league and release players, and we support it - but I hope that common sense will prevail."
Meanwhile Europe's top clubs warned FIFA to pay more attention to their demands or risk a new club versus country cold war.
Following their general assembly, the ECA also expressed their dissatisfaction over FIFA president Sepp Blatter's constant public pronouncements about whether the Qatar 2022 World Cup would be staged in winter or summer.
Calling for a greater role in the decision-making process of the international match calendar, Sandro Rosell, the president of Spanish champions Barcelona and an ECA vice-president, did not mince his words, saying: "I wouldn't say we are at war, the clubs are very patient, but we have our limits.
The clubs are angry that FIFA have added eight additional international fixtures to the match calendar from 2011-14, including today's (Wednesday) round of friendlies across Europe, seemingly without consulting them.
Gandini said the current schedule suited no-one, adding: "Tell me which national team manager or club manager is happy there is an international friendly tomorrow (Wednesday)?
"All of a sudden we discover they (FIFA) can modify the calendar any time they like. If you are not heard you have to scream."
The ECA also underlined its opposition to playing the Qatar 2022 World Cup during the winter even though summer temperatures could reach 50 degrees in the searing desert heat.
Gill was clearly aggrieved that no proper discussions had been held with the clubs.
"It has not been dealt with correctly," he said. "There has been concern obviously in the way it has manifested itself. That is not just our view, it's the view of more than 100 clubs individually and collectively.
"This is a major thing that will have ramifications for club football for three years. For it to happen in that way was somewhat surprising. This is an issue that has not been dealt with correctly."
