AN independence vote set for November in Spain's powerful Catalonia region has been halted by the nation's constitutional court after the central government mounted a legal case saying the planned referendum would be illegal.

The court's unanimous decision to hear the government's case automatically suspended the November 9 vote from going forward until the court hears arguments and makes a decision. That process could take months or years.

The Spanish government contends the vote approved on Saturday by Catalan regional leader Artur Mas is unconstitutional.

The court acted after Prime Minister Mariano Rajoy said the referendum decree represents "a grave attack on the rights of all Spaniards".

Under Spain's 1979 Constitution, Mr Rajoy said, all Spaniards must vote on issues of sovereignty - not just the five million Catalans who would be eligible to vote under Mr Mas's planned vote.

Unhappy at Spain's refusal to give it more autonomy and fiscal powers, and buoyed by the vote in Scotland, albeit not the result, Catalan politicians have been pushing for the referendum for months.

Polls suggest most Catalans favour holding the vote but are roughly evenly split on independence.

Mr Mas has insisted the vote will happen but has also said Catalonia will not break any laws.