LaLiga president Javier Tebas warned that expanding the World Cup to 64 teams would represent the continuing destruction of the football industry under FIFA president Gianni Infantino, whom he called on to resign.
Tebas, 63, has regularly criticized Infantino and launched another attack on him as the dust settles on the 2026 World Cup.
Spain will co-host the next edition of the finals in four years time, along with Portugal and Morocco, and there have been suggestions the tournament will be increased from 48 teams to 64.
"Increasing the number of national teams makes no sense," Tebas said in an interview with Italian newspaper La Gazzetta dello Sport which was published on Tuesday.
"The football industry is not just the World Cup, which is the most important event.
"But not everything can revolve around the World Cup. It is national competitions that support this sport.
"They are destroying the football industry, the one that generates tens of thousands of jobs, for an event that lasts 40 days and to which only the minority of players go.
"We need fewer national teams and more protection for national football, at all levels. They don't realize; they decide irresponsibly."
The World Cup in North America this summer was the first to feature 48 teams, with the tournament having previously included 32 national sides since its expansion from 24 for the 1998 edition.
There has also been criticism for FIFA and Infantino throughout the last six weeks over several issues related to the tournament held in the United States, Canada and Mexico.
There have been complaints about enforced hydration breaks, visa issues for people arriving in the USA for the tournament and the furor surrounding the Folarin Balogun saga, when U.S. President Donald Trump and the American government worked to help U.S. Soccer have the striker's suspension overturned.
Despite all that, Infantino, 56, is expected to be reelected for a fourth term at FIFA's March congress, although Tebas believes he should walk away.
"In my opinion, yes [he should resign], I think [he] has had his day," Tebas added. "But he has the support of the system, of the federations, there is not much more to add, right?
"There is no opposition candidate, no one wants to present themselves to lose. This is the system and it is a system that is sick at the source.
"In these days here in America I have heard many people against Infantino, who do not agree with what he does. They say it, but then they do nothing.
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"I don't know if silence or complicity is worse, because those who are silent are perfectly aware of the damage that football is suffering.
"The overturning of the American player's suspension [Balogun] is something of absolute gravity. They were lucky because Belgium eliminated the USA [in the round of 16], because otherwise a case could have been created that could have cost Infantino his job.
"Since Belgium won, they managed to bury the thing. But these things are only the tip of the iceberg.
"FIFA fixes things as it wants, for what it wants, for its interests, certainly not for football. And so if they need 27 minutes of interval they do it. Hydration breaks are a lie.
"We have them in LaLiga, but when it's really hot. Here, the stadiums in Dallas, Los Angeles and Atlanta had air conditioning -- I had to put on a sweater in the stands. It was a lie, a break for advertising."
