Concacaf president Victor Montagliani has criticised a proposal to expand the 2030 men's World Cup to 64 teams.
The plans, put forward by South American governing body Conmebol, have also drawn opposition from Uefa president Aleksander Ceferin and the Asian Football Confederation (AFC).
The tournament will be hosted by Spain, Morocco and Portugal, after the opening matches are held in Argentina, Paraguay and Uruguay.
The 2026 World Cup, which will take place across the United States, Mexico and Canada, has already been expanded from 32 to 48 teams.
But Conmebol said it wanted to add more participants to mark the competition's 100-year anniversary.