Spain’s King Felipe VI says Catalan authorities have deliberately bent the law with “irresponsible conduct” and the Spanish state needs to ensure constitutional order and the rule of law in Catalonia.

Delivering an address to the nation by television on Tuesday, the king said 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,” Felipe said, referring to the political crisis as “very serious moments for our democratic life”.

The state needs to ensure Spain’s constitutional order and the correct functioning of Catalan institutions and rule of law, he said.

Hundreds were injured in a violent police response to Catalan’s bid for independence. Photo: Getty

Spain’s conservative government has said it will respond with “all necessary measures” to counter the Catalan defiance.

It is holding talks with national opposition leaders to find multi-partisan consensus on the response, which could include suspending the region’s self-government.

Meanwhile, tens of thousands of people are joining marches across Barcelona in an outcry against police violence that has united political views that only one week ago seemed irreconcilable.

Separatist groups and unions had initially called for strikes to be held on Tuesday in support for Catalan leaders pushing ahead with a declaration of independence from Spain. But many non-separatists were also drawn to the streets following a crackdown on an unauthorised referendum Sunday.

Some 90 per cent of voters in an in the referendum backed Catalan independence.

Catalan residents took to the polls and the streets throughout Sunday in a day of chaos that saw at leat 844 civilians injured by Spanish riot police.

Police smashed their way into Catalan polling stations to try to halt a disputed referendum on independence, while rubber bullets were fired into demonstrating crowds and voters were attacked during the daylong melee.

Spanish Prime Minister Mariano Rajoy insisted there was no independence referendum in Catalonia and praised police, saying they acted with “firmness and serenity” in response to the vote.

Police broke down doors to force entry into voting stations as defiant Catalans shouted “Out with the occupying forces!” and sang the anthem of the wealthy northeastern region.

Officers in riot gear hit people with batons and forcibly removed would-be voters, including women and the elderly, from polling stations.

The referendum, declared illegal by Spain’s central government, has thrown the country into its worst constitutional crisis in decades and deepened a centuries-old rift between Madrid and Barcelona.

“On this day of hope and suffering, Catalonia’s citizens have earned the right to have an independent state in the form of a republic,” Catalan governor Carl Puigdemont later said in a televised address.

“My government in the next few days will send the results of today’s vote to the Catalan Parliament, where the sovereignty of our people lies, so that it can act in accordance with the law of the referendum,” he said.