Barcelona’s Nou Camp was due to play host to the fixture between the two La Liga giants on October 26.
However the recent jailing of nine Catalan political leaders has sparked confrontation within the city, with a demonstration rally now planned for the same date.
The Spanish soccer federation (RFEF) announced the news on Friday morning and revealed that the rearranged date will be confirmed by Monday.
A statement said: “FC Barcelona and Real Madrid must agree on the new match date.
“Gathered on an extraordinary day yesterday the RFEF Competition Committee, has resolved in relation to the National League Championship game between FC Barcelona and Real Madrid set for next October 26, after analysing the allegations of the parties , the next:
“- The regulation prevents the alteration of the order of dispute of the parties established in the calendar.
“- The Committee lets the affected clubs reach an agreement to find the classic dispute date. FC Barcelona and Real Madrid will set the date and time in the next hours, with Monday October 21 at 10:00 a.m. as a limit.
“- In case of not reaching an agreement, the Competition Committee will be the body responsible for determining the date of the meeting.”
The El Prat airport in Barcelona was temporarily closed on Tuesday due to the rising tensions, with almost 100 people reported to have been arrested since Monday.
Nearly 200 officers are also said to have been injured as a result of escalating violence, and the Royal Spanish Football Federation (RFEF) have now laid down proposals to move the tie.
Officials will now agree on a new date to hold the fixture, with the federation having final say.
A date of December 7 has now been suggested, which as it is a Saturday, would involve moving both sides’ Copa del Rey fixtures currently scheduled for that day as well.
La Liga are against the idea of staging the El Clasico fixture during midweek as it would likely harm viewing figures and have a knock-on effect to television rights holders.
The news comes after Barcelona boss Ernesto Valverde revealed his hope that the game would go ahead.
“This game can perfectly take place – it’s a good opportunity to play it with normalcy,” he said. “It’s a good opportunity to do so against all those that are pessimistic. [Oct. 26] is the date it was set… This is my opinion, but I don’t know what decision the [competition committee of the Spanish FA] will take.
“There are nine days left to play, and the normal thing would be to play in our stadium. If you told me the game was today or tomorrow, then fine. But we still have time. It’s an important game for people to see. It should be played under normal circumstances.
“We would go into the game having one day less to rest than Real Madrid, so I guess if you look at it that way, it would be us [to suffer]. However, in these type of games that is not that important, as players are always ready to play these games.”