The court has ordered the suspension of Monday’s session of the regional Catalan parliament, where the declaration for unilateral independence from Spain was billed to take place.
The speaker of the Catalan parliament, Carme Forcadell, accused the Madrid government of using the courts to deal with political problems and said the regional assembly would not be censored.
But she said parliamentary leaders have not decided whether to defy the central court and go ahead with the session.
The suspension order further aggravated one of the biggest crises to hit Spain since the establishment of democracy on the 1975 death of General Francisco Franco.
But Spanish markets rose on perceptions the order might ward off, at least for now, an outright independence declaration.
Spanish Prime Mariano Rajoy called on Catalan leader Carles Puigdemont to drop independence plans or risk “greater evils”.
Secessionist Catalan politicians have pledged to unilaterally declare independence at Monday’s session after Sunday’s referendum, banned by Madrid and marked by violent scenes where Spanish police sought to hinder voting.
The constitutional court said it had agreed to consider a legal challenge filed by the anti-secessionist Catalan Socialist Party.
Spanish shares and bonds, hit by the political turmoil in Catalonia, strengthened after the news of the court’s decision. The main IBEX stock index rose 2.5 percent and the yield on Spain’s 10-year bond fell.
Spain’s Economy Minister Luis de Guindos told Reuters in an interview the turmoil was damaging Catalonia.