The ECA, the interest group of top clubs in European football, took a statement to FIFA on Friday.
The organization is especially not happy with the World Football Association's plan for a biennial World Cup.
FIFA is currently commissioning a feasibility study for a World Cup every two years, instead of the current four-year cycle.
Arsene Wenger, FIFA's chief of football development, is "100 percent convinced" of this move.
On Wednesday, UEFA called on FIFA to stop the plans.
The ECA, which includes Ajax, PSV, Feyenoord, AZ, Vitesse, FC Utrecht, FC Twente and sc Heerenveen, is now joining this.
FIFA's proposals would have a devastating impact on club football, both nationally and internationally, putting players' health at risk, the ECA writes.
"It is with great concern and concern that we follow the launch of an active public relations campaign and much clean-up by FIFA, apparently aimed at bringing about reforms to the fixtures calendar, notably the introduction of a biannual World Cup."
Infantino speaks with government leaders in New York
FIFA President Gianni Infantino is in New York this week for the United Nations General Assembly.
Infantino has agreements with various government leaders, including Turkish President Recep Tayyip Erdogan and British Prime Minister Boris Johnson.
FIFA communicates extensively about this and regularly reports that the future of the competition calendar has been discussed in those conversations.
Various national coaches, including Sarina Wiegman and Mark Parsons, already spoke out this week against a World Cup that is held every other year.
According to FIFA, a majority of football fans do like it.Keywords: