The biggest match in world football was due to be played on October 26 at the Camp Nou in Barcelona.
Both clubs have now been told that they must agree to a new date by 10am on Monday or the competition committee will determine the date for them.
La Liga feared a match with an estimated global TV audience of 650m viewers will be used as platform for protests against this week’s Spanish Supreme Court sentencing of nine Catalan separatist leaders to prison terms of between nine and 13 years for their part in a referendum held in defiance of the Spanish Constitution in 2017 and a subsequent declaration of independence.
The Spanish league have suggested to the Competition Committee to play the match on a weekend as opposed to the original suggested date of December 18 which is a Wednesday.
La Liga believe that moving it to midweek would mitigate the global impact of the match.
Barcelona are due to play Real Mallorca on matchday 16 whilst Real Madrid were meant to welcome Espanyol.
La Liga president Javier Tebas would need to meet with Mallorca and Espanyol chiefs to agree to the proposal.
Should El Clasico take place on December 7, it will come just two days before Zidane’s side travel to Belgium to play Club Brugge.
Ernesto Valverde’s men will travel to Milan to take on Inter on December 10.