Carles Puigdemont, the former leader of Catalonia who fled Spain over his role in a failed 2017 independence bid for the wealthy region, 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.

"I have come here to remind you that we are still here," he said 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.

It was not immediately clear where he was.

Nuria Pujol, a woman in her fifties who came to Barcelona from the Alt Penedes region to see Puigdemont, called him "a very noble person".

"The only one who believes in independence and has not stopped believing," she added.

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