The Catalan Parliament this week agreed to a resolution to censure King Felipe and call for the abolition of the monarchy.
The move was in response to the King’s speech last year in response to the region’s illegal referendum on independence.
Pro-independence parties were divided earlier this week and were unable to approve the motion.
But left wing parliamentarians who are not pro-independence moved a resolution of their own, which succeeded.
The Socialist central government said it would challenge the resolution as against the Constitution and the Head of State.