Barcelona: Catalonia will apply the law that calls for a declaration of independence following a majority 'yes' vote, Catalan leader Carles Puigdemont says in a television program to be broadcast later on Sunday, local time.

"The declaration of independence, that we don't call a 'unilateral' declaration of independence, is foreseen in the referendum law as an application of the results. We will apply what the law says," Puigdemont says in the program on Catalonia's TV3, according to excerpts on the broadcaster's website.

People on a rooftop wave Spanish flags during a march in downtown Barcelona, Spain, to protest the Catalan government's push for secession from the rest of Spain, on Sunday. Credit:AP

The Catalan government says more than 90 per cent of people who voted in the October 1 referendum voted in favour of independence from Spain. The referendum was declared illegal by Spanish authorities and turnout was only 43 per cent.

The Catalan law paving the way for the referendum said the Parliament of Catalonia would declare the region's independence within 48 hours of a "yes" vote being proclaimed by the Catalan electoral office.