Spain's Constitutional Court had provisionally blocked their plan for the vote, but parties in the northeastern region opted to launch a legal gamble.

"We have agreed to maintain the election decree so that citizens can exercise their right to vote on November 9," the Catalan regional government spokesman Francesc Homs told reporters in Barcelona.

Catalan pro-independence parties declared they were "united" on the issue to the press, after holding meetings to forge a common front in the tense standoff, which threatens to trigger Spain's biggest constitutional crisis in decades.

The central government has vowed to keep Spain whole against the drive for independence for Catalonia.