Leading MotoGP riders called Thursday for the season finale in a fortnight to be moved out of Valencia because of deadly once-in-a-generation flooding in Spain.

At least 95 people have been killed and troops, police and firefighters are racing to find survivors and victims in the Valencia region of the country.

The MotoGP world title could go down to the final race weekend of the campaign, scheduled for the Circuit Ricardo Tormo just outside Valencia on November 16-17.

"At the end of the day, I think the best solution will be to race elsewhere," said Spain's Jorge Martín, who tops the championship ahead of Italy's title-holder Francesco Bagnaia.

Speaking in Sepang ahead of this weekend's Malaysia GP, the 26-year-old called on the sport's bosses to make a decision on a possible change of venue as soon as possible.

"The best thing would be to know right now so you approach the weekend in a different way," said the Pramac Ducati rider.

Title rival Bagnaia, who is still in the fight just 17 points back, said the Spanish people "are living their worst dream".

"Knowing the situation as it is, it's not correct – this could be wrong to race there. If it was my choice, I'd prefer not to race there. We have many other options," said the Ducati rider.

The Valencia track itself has not been damaged but there are question marks about some of the other infrastructure needed to host thousands of fans.

Six-time MotoGP world champion Marc Márquez said the priority must be the recovery effort and not racing.

Up to a year's rain fell in a few hours on the eastern city of Valencia and the surrounding region on Tuesday, sending torrents of water and mud through towns and cities.

"As a Spaniard, it's super-difficult to see these kinds of images," said Márquez. "Theorically, we have a GP there – but now I think all the facilities of the government, of Spain, need to go to the people who lost their houses."

Spain on Thursday started three days of mourning. (AFP)