President Carles Puigdemont has asked to address Catalonia's parliament on Tuesday, after Spain suspended a session scheduled for the day before at which the region was widely expected to declare independence in direct defiance of Madrid.

Around 40 per cent of the region's 5.5 million electors voted in a referendum last weekend that Madrid had ruled illegal and deployed riot police to disrupt.

Ballot boxes were shipped in from France by night, stored in homes and improvised hiding places, then secretly shuttled to polling stations.

Catalan officials said police had closed or raided 400 of the more than 2,000 polling stations before or during the vote but added that 2.2 million votes were cast, with 90 percent in favour of breaking away.

However, the last regional election and polls showed the 7.5 million residents of Catalonia were almost evenly divided on the issue, and many who would rather stay part of Spain are not thought to have taken part.

Nevertheless, Mr Puigdemont vowed to declare independence based on the result, after which Spain suspended a Catalonian government session for assessing the vote that had been due to take place on Monday amid speculation he would use it to do so.

Mr Puigdemont now wants to use Tuesday's planned address to "report on the current political situation", according to a brief statement by his office.

In Madrid, Spain's National Court unconditionally released two senior officers of Catalonia's regional police force and the leaders of two pro-independence civic groups who are being investigated for sedition in connection with the referendum.

The four are to be questioned again in coming days.

The case is linked to demonstrations on September 20-21 in Barcelona, when Spanish police arrested several Catalan government officials and raided offices in a crackdown on preparations for the referendum.

The four being investigated are Catalan police chief Josep Lluis Trapero, Catalan police lieutenant Teresa Laplana, Jordi Sanchez, the head of the Catalan National Assembly, and Jordi Cuixart, president of separatist group Omnium Cultural.

After being questioned for about an hour, Mr Trapero left the courthouse to applause by Basque and Catalan party representatives and insults from bystanders.

Mr Sanchez also answered questions related to his defence.

"I ask strongly that the Spanish government, the national parliament and the head of state (the king) understand that time and the hours are very important to find a debated solution and give way to a political solution," Mr Sanchez said.

Spanish authorities say the demonstrations hindered the Spanish police operation, and that Catalan police didn't do enough to push back protesters blocking Spanish police officers from leaving a building. Two police cars were vandalised and officers were caught inside the building for hours.

Spain's conservative government has refused to enter into talks on the crisis unless the Catalans drop plans for secession.

Neutral Switzerland has offered to mediate and is in touch with both sides but admits talks look unlikely to happen.

"Facilitation can only be provided if both parties request it. Switzerland is in contact with both parties, but the conditions for facilitation are not in place at this stage," a foreign ministry spokesman said.

He described the situation in Catalonia as an internal Spanish political matter and said Switzerland respected the sovereignty of Spain.

Spain's government also approved a decree that would make it easier for companies in Catalonia to move the location of their official registration out of the region.

The move will allow the relocation of Caixabank, Spain's third largest bank by assets, before next week.

Catalonia independence referendum: Riot police clash with voters Show all 17 1 /17 Catalonia independence referendum: Riot police clash with voters Catalonia independence referendum: Riot police clash with voters A man faces off Spanish Civil Guards outside a polling station in Sant Julia de Ramis Reuters Catalonia independence referendum: Riot police clash with voters Riot police form a security cordon around the Ramon Llull school in Barcelona EPA Catalonia independence referendum: Riot police clash with voters Riot police evict a young woman during clashes between people gathered outside the Ramon Llull school in Barcelona EPA Catalonia independence referendum: Riot police clash with voters Spanish Civil Guard officers break through a door at a polling station in Sant Julia de Ramis Reuters Catalonia independence referendum: Riot police clash with voters Spanish National Police clash with pro-referendum supporters in Barcelona on Sunday AP Catalonia independence referendum: Riot police clash with voters Crowds raise their arms up as police move in on members of the public gathered outside to prevent them from voting in the referendum at a polling station where the President Carles Puigdemunt will vote later today Getty Catalonia independence referendum: Riot police clash with voters People confront Spanish Civil Guard officers outside a polling station Reuters Catalonia independence referendum: Riot police clash with voters Three man hold each other as they try to block a Spanish police van from approaching a polling station AP Catalonia independence referendum: Riot police clash with voters A woman shows a ballot to a Spanish Civil Guard officer outside a polling station Reuters Catalonia independence referendum: Riot police clash with voters A man wearing a shirt with an Estelada (Catalan separatist flag) and holding carnations faces off with a Spanish Civil Guard officer Reuters Catalonia independence referendum: Riot police clash with voters Police try to control the area as people attempt to cast their ballot at a polling station in Barcelona Getty Catalonia independence referendum: Riot police clash with voters A man is grabbed by officers as police move in on the crowds Catalonia independence referendum: Riot police clash with voters Two women argue with a Spanish National policeman during clashes between Catalan pro-independence people and police forces at the Sant Julia de Ramis sports centre in Girona EPA Catalonia independence referendum: Riot police clash with voters Sant Julia De Ramis in Spain Getty Catalonia independence referendum: Riot police clash with voters Confrontation outside a polling station in Barcelona, where police have tried to stop people voting AFP/Getty Images Catalonia independence referendum: Riot police clash with voters A Spanish National Police officer aims a rubber-bullet rifle at pro-referendum supporters in Barcelona AP Catalonia independence referendum: Riot police clash with voters Riot police clashed with voters as polls opened in Barcelona Sky News

At least half a dozen companies, including the fifth-largest lender, Banco Sabadell, have already relocated or agreed to do so.

The moves have no immediate effect on jobs or company assets, but are seen as a blow to the Catalan government.