Catalonia 'Republic Now' march draws tens of thousands as demonstrators asked the formation of a new government in Spain's Catalonia region leading to its independence from Madrid despite formidable legal obstacles.

Some 45,000 people joined the "Republic Now" march called by the influential pro-independence citizens' group ANC, city police said.

Separatist parties won an absolute majority of seats in the 135-seat Catalan parliament in a snap election on December 21 but have so far failed to form a new government.Catalonia's two main separatist parties last week proposed a new referendum on a constitution of the "Catalan republic".

The region of 7.5 million people has been under direct rule from Madrid since Prime Minister Mariano Rajoy dissolved the Catalan parliament last October following an independence referendum not recognised by Madrid.