Double world champion Fernando Alonso is set to join Ferrari next season with a decision coming as soon as next weekend at the Japanese Grand Prix, reports said yesterday.

Speculation has been rife in the F1 paddock of an impending move and the driver himself said his mind was made up.

"I don't think the podium changes the decision on who I drive for next season," he said after finishing third for Renault at the Singapore Grand Prix.

"I have taken the decision already. You will know soon."

The respected autosport.com website said lawyers had been working hard on the last few details of Kimi Raikkonen's release from his contract with Ferrari, a move that is likely to pave the way for the Finn to return to McLaren.

It said everything could be sorted out by next weekend, with Alonso partnering Felipe Massa, now back in training after the severe injuries he sustained at the Hungarian Grand Prix in July.

"I think that as soon as we are ready we will let you know. We don't want to wait too long," Ferrari team principal Stefano Domenicali said.

When asked if that announcement could come as early as Suzuka, Domenicali said: "It is a possibility but it is not guaranteed."

Renault's stand-in managing director, Jean-Francois Caubet, said he would be sad to see Alonso leave.

"I think Fernando will miss Renault and Renault will miss Fernando," he said.

Once the Alonso announcement is made, autosport.com said Renault were expected to confirm Polish driver Robert Kubica will lead the team in 2010.

Alonso's departure has looked even more likely since former Renault team boss Flavio Briatore, who guided the Spaniard into F1, was handed a lifetime ban from the sport for his role in fixing last year's Singapore race.

Renault were handed a suspended permanent ban.

"Obviously, now we have had these recent problems, I would like to dedicate my third place to Flavio, who watched this race at home," Alonso said.

"Part of this success is down to him and he will be pleased for the team and it deserves it too as it has been difficult for everyone, the mechanics ... engineers."

"Hopefully we can put all the bad things behind us and this is a new starting point."

Elsewhere, Rubens Barrichello is reportedly fighting to stay at Brawn GP with Williams driver Nico Rosberg tipped to replace the veteran Brazilian.