MADRID -- Two parties holding a majority of seats in Catalonia's new regional parliament on Tuesday presented a motion for the chamber to announce the formal start of secession from Spain and the formation of a new republican state of Catalonia.

The proposition was presented by the "Together for Yes" pro-independence alliance that won 62 seats in Catalonia's 135-member parliament in September elections, along with the radical leftist CUP party, which won 10 seats.

The parties called for the Barcelona-based parliament to vote on the motion urgently but it is unlikely to have more than symbolic importance as the region has yet to form a new government.

No date was set for the vote.

The motion calls on parliament to pass laws within 30 days that would allow the region push ahead toward a separate constitution, social security system and treasury.

It also says the process would not be subject to decisions made by the Spanish institutions, including the constitutional Court.

Spanish Justice Minister Rafael Catala said such a motion would lack legal significance but, if approved, the government will study whether it needs to be challenged in court.

The "Together for Yes" alliance is headed by acting regional President Artur Mas, who after failing to get a majority is now in negotiations with the CUP to try to form a new government. The CUP, however, has said it will never support Mas as president, making the formation of a new government a difficult task.

Mas has promised to set Catalonia on a path toward independence by 2017 if he gets a majority.

Although the pro-independence camp won 72 seats, it got only 48 per cent of the popular vote. This is because Spain's electoral system gives more seats to votes from rural areas, where secession sentiment is strong in Catalonia. Most of the remaining parties are strongly opposed to independence.

Spain has ruled out any possibility of Catalonia becoming independent, saying it goes against the country's constitution.

Polls show Catalans overwhelmingly support the right for a secession referendum but are evenly divided over independence.

The region of 7.5 million people is responsible for nearly a fifth of Spain's economic output.