The Royal Belgian Football Association (RBFA) have insisted that Real Madrid must reach an agreement with them first in order to appoint Roberto Martinez as their new coach.
Santi Solari has been temporarily placed in charge at the Santiago Bernabeu following the sacking of Julen Lopetegui in the wake of a 5-1 El Clasico defeat to Barcelona.
Madrid have won just one of their last seven matches in all competitions and sit ninth in La Liga, seven points adrift of defending champions and leaders Barca.
Antonio Conte was thought to be the leading contender for the position, but Goal has reported negotiations with the former Chelsea head coach are dragging on.