Spain risks intensifying Catalonia's push for independence unless it negotiates over transferring more powers, according to the region's economy minister.

The country's government asked the constitutional court last month to declare a November 9 referendum illegal on the grounds it breached the constitution. The court suspended the vote until it ruled on the case, which could take years.

Catalan President Artur Mas has now dropped plans for a binding vote and will instead hold a "consultation of citizens" which he said would be within the law.

"Sooner or later there will have to be dialogue or negotiation," Catalan Economy Minister Andreu Mas-Colell said in an interview in London. "We are not going to retire."

He hoped the Catalan government would see out its term but said clamour for early elections would grow if the Spanish government refused to discuss greater autonomy for Catalonia.

"If the possibility of consultation is denied us, the pressure to call elections will naturally increase," he said.

About half of Catalans want more independence from Spain and an overwhelming majority want a say on their future, opinion polls show.

Some want Mas to call early elections as a proxy vote on secession, a move likely to benefit the more radical independence party ERC, a coalition partner of Mas's CiU.