The Catalan authorities have deliberately bent the law with their "irresponsible conduct", Spain's King Felipe VI has said.

Delivering an address to the nation by television, the king said that the bid by authorities in the northeastern region to push ahead with independence has "undermined coexistence" in Catalonia.

"Today, Catalan society is fractured and confronted," King Felipe said, referring to the political crisis as "very serious moments for our democratic life".

He said that the state needs to ensure Spain's constitutional order and the correct functioning of Catalan institutions and rule of law.

Spain's conservative government has said it will respond with "all necessary measures" to counter the Catalan defiance, and is holding talks with national opposition leaders to find multi-partisan consensus on the response, which could include suspending the region's self-government.