The former leader of Catalonia who fled Spain over his role in a failed 2017 independence bid for the wealthy region, Carles Puigdemont, returned to Spain on Thursday after seven years on the run despite a pending arrest warrant.

Puigdemont shouted "Long live a free Catalonia!" as he climbed onto a stage in Barcelona to address thousands gathered near the Catalan regional parliament which is set to elect a new leader later in the day.

He said his mission was to remind them to stay strong, as many in the crowd waved red, yellow and blue Catalan independence flags.

After his brief address, Puigdemont appeared to head towards the nearby Catalan parliament but the assembly began an investiture vote to pick a new leader for the region without him being present.

Meanwhile, in a demonstration organised by far-right party Vox a small group of protesters gathered waving Spanish flags and holding signs that read  "Catalonia is Spain

Puigdemont's dramatic return came just days after Spanish Prime Minister Pedro Sanchez's Socialists struck a deal with moderate Catalan separatist party ERC, which competes with Puigdemont's more hardline JxCAT.

The Socialists won the most seats in a regional election in May but failed to get a majority as the support of the ERC is crucial.

Puigdemont led the regional government of Catalonia in 2017 when it pushed ahead with an independence referendum despite a court ban, which was followed by a short-lived declaration of independence.

He fled Spain shortly after the independence bid to avoid prosecution and has since lived in Belgium and more recently France.