LISBON (Reuters) - Dozens of demonstrators gathered at the Tesla showroom in Lisbon on Sunday to protest against CEO Elon Musk's support for far-right parties in Europe as Portugal heads toward a likely snap election.

Musk has used his X platform to promote right-wing parties and figures in Germany, Britain, Italy and Romania. He has not waded into politics in Portugal where the far-right Chega party has surged to become the third largest force in parliament.

In the capital Lisbon, protesters held up signs about U.S. President Donald Trump and his billionaire adviser Musk, with some reading "Boycott Tesla".

Nuno Raimundo, 54, a doctor in Lisbon, said "it was time for people around the world to stand up" and counter Trump's leadership and Musk's promotion of the far right in Europe.

"Otherwise, history will return to the 1930s in Europe", he said. "(Musk) may not be able to have enough influence in the next election in Portugal but with the amount of money he has, step by step, he can do that."

Portugal plunged into a new political crisis after Prime Minister Luis Montenegro's centre-right government on Thursday approved a confidence vote in his year-old minority government, risking his own dismissal.

President Marcelo Rebelo de Sousa said a fresh election, which would be the third in three years, could take place on May 11 or May 18.

The centre-right alliance is polling at around 30%, slightly ahead of the Socialists, with Chega in third on 18%.

Musk's political postures appear to be coming at a price for Tesla, whose sales in Europe tumbled 45% in January from a year earlier, while its rivals' sales rose by over 37%, according to the European Automobile Manufacturers Association.

(Reporting by Sergio Goncalves and Pedro Nunes; Editing by Ros Russell)