On Sunday night 12 European football clubs announced the formation of new competition, the Super League, to widespread criticism from governments, their own domestic leagues, football federations as well as Uefa and supporters around the world.
It would be the biggest shake-up in the history of the European game although Uefa has said it will fight what it called "a cynical project founded on the self-interest of a few clubs".
In a statement on Monday, La Liga said it "strongly condemned" the proposal for a breakaway European Super League.
"La Liga strongly condemns the recently published proposal for a breakaway, elitist European competition that attacks the principles of open competition and sporting merit which are at the heart of the domestic and European football pyramid," said the Spanish league.
"Today football fans across Europe can dream that their club, no matter the size, may excel, climb to the top and compete at the pinnacle of European football. La Liga defends this European tradition of football for all.
"The concept proposed by 12 European clubs destroys that dream, shutting the door to the top of European football, allowing in just an elite few."
It has been rumoured that this season's La Liga campaign could be cancelled.
Teams would play 10 matches each in the group stage rather than the six they currently play and a playoff round would also be introduced before the last 16.
There have been reports of a plan for a breakaway league for a number of years and the speculation returned in January with several media reports that a document had been produced outlining the plans for a 20-team league.
Those reports led Fifa and Uefa to warn they would ban any players involved in a breakaway from playing in the World Cup or European Championship.