Real Madrid and Barcelona must decide when the first "Clasico" of the season is to be played after the Spanish Football Federation's (RFEF) confirmation it has postponed the fixture.
The match had been scheduled for Saturday, October 26 but concerns over political unrest in Catalonia means the kickoff has been put back.
"Barcelona and Real Madrid should agree the new date for the match before October 21," a RFEF statement on Friday said.
"In the case of them failing to do that, it will be RFEF's competitions committee that sets the new date."
RFEF has proposed Wednesday, December 18, as a new date for the game at the Camp Nou.
Reports in Spain suggest both clubs will accept that date but the Spanish League is unhappy because there is a Wednesday program of Copa del Rey games - albeit not involving Barcelona and Real Madrid - on that date.
Australian Associated Press