Eintracht Frankfurt wants to stop parts of the Champions League reform with several clubs from the European middle class.
From 2024 onwards, 36 instead of 32 teams will take part in the premier class of football.
Two places are to be awarded on the basis of previous results and not performance in the previous season of the national league.
"When you take part in the Champions League, your coefficient keeps getting higher, it's becoming more and more of a closed system," said Frankfurt's board spokesman, Axel Hellmann, according to the AP news agency.
"The national qualification is the most important door that should be kept open."
The UEFA Executive Committee approved the reform a year ago.
Shortly before, twelve top European clubs had published their plans for a Super League to compete with the Champions League.
However, these initially failed.
The merger of the European leagues is also hoping for changes to the premier class reform.
"We have to prevent that"
Hellmann advocated a stronger financial balance within the European competitions.
“The other alternative is clear.
If we don't do this to a certain extent, we create our own monster.
Champions League clubs will generate more and more money and one day they will try to enter a Super League because it is the only way to meet their economic needs," said Hellmann.
"And we have to prevent that."
Frankfurt take on West Ham United in the Europa League semi-final first leg on Thursday.
If Eintracht wins the second tier European competition, they will play in the Champions League next season.
"I think the difference between the Europa League and the Champions League is too big," said Hellmann.
His club is working with other teams in an initiative "to strengthen the interests of European middle-class clubs."