• Finn says Lotus have not paid his salary or bonuses • Raikkonen had to be persuaded to drive in Abu Dhabi GP

Kimi Raikkonen has threatened to walk out on Lotus and miss the last two races of the season unless he is paid what he claims are the missing millions from his salary and bonus package.

Raikkonen, 34, the 2007 world champion who made a successful return to Formula One with Lotus last year, also said he was close to missing Sunday's Abu Dhabi Grand Prix. "I came here only because hopefully we found an understanding on the certain issues we have been having," he said. "Hopefully it will be fixed and we can finish the season as well as we can."

Raikkonen is expected to race after flying into Abu Dhabi a day later than the other drivers. But when asked whether he would consider not taking part in the final races in the United States and Brazil later in the month he said: "For sure. I enjoy racing, I enjoy driving – but a big part of it is business.

"Sometimes when that is not dealt with like it should we end up in an unfortunate situation. You have to put the line somewhere, and if it goes over that ... it is not really my fault any more."

Raikkonen is thought to be the third best-paid driver in Formula One after Fernando Alonso and Lewis Hamilton. But his package is heavily weighted with bonuses and it these that cash-strapped Lotus have struggled to pay, according to Raikkonen. He has simply driven better than they expected.

He has already signed for Ferrari for next year but his last spell with Lotus is ending with bitterness. It reached a new level in the last race in India on Sunday when he had a heated exchange with the trackside operations director Alan Permane, who swore at Raikkonen while telling him to get out of the way so that his faster team-mate Romain Grosjean could get past.

Raikkonen added: "Everybody has their own view, own ideas of everything. Sometimes it's not very nice when you hear that you don't have the interests of the team. And you've been paid zero euros the whole year it doesn't put you in the best place, but that's how it goes and hopefully we found an understanding on both sides about how we should deal with the situation."

The Lotus team principal Eric Boullier said: "Kimi has some emotions. He's not as ice man as we all believe he is. He's a normal guy." Asked whether he had a reserve driver lined up for this weekend's race he replied: "We always have."

Regarding the team's finances, he said: "We are talking to bring the team to the next step in terms of finances and resources. We nearly have it. Depending on the scenario, it may change the driver lineup.

"We want to carry on the nice story but there is some reason why Kimi's leaving. We have the highlights on us. But it's not only about us. The costs are too high in F1. To be competitive you have to spend at least a minimum of 50% of the top teams. It still a lot of money and it's not sustainable."

With reference to the radio row, Boullier added: "There was one word in the phrase which when you get stressed and emotional it can create more emotions."

Meanwhile, Alain Prost says Hamilton will not win another Formula One world championship unless he changes his approach to the sport.

Prost, a four-times champion who is recognised as one of the all-time greats, said: "The way Sebastian Vettel works with people in the team, we know that he is doing little things different to the rest. That gives him an advantage and makes him more confident. That's why it is always a package.

"On the other side, there is a guy like Lewis who is more of a pure racing driver but I think he should change a little bit and look into other things because he could be surprised.

"Now you are not driving by yourself. You are going to have all this computerised equipment behind you and you might get a different reaction.

"Maybe next year he will find another motivation, but at the moment he is finding it very hard to beat Sebastian, because the way he has his team behind him, maybe Lewis needs to have something different."

Hamilton admitted he might not win another title when he said: "I have confidence we'll be competitive next year but you never know. Maybe circumstances mean that I never win the world championship again. It could happen in our sport, who knows."