Kimi Raikkonen says the decision about his future plans won't be an easy one to make, with speculation set to increase about the possibility of the Finn leaving Lotus at the end of the year.

The former title winner has impressed since returning to the grid with the Enstone-based team last year and had been mentioned as a possible replacement for Mark Webber at Red Bull if the Australian elected to leave the team at the end of the season.

With Webber having now confirmed he will walk away from F1 to return to sportscars for 2014, Red Bull is searching for a new team-mate for Sebastian Vettel, with Raikkonen set to feature near the top of the shortlist of possible options.

However, the 33-year-old - who Red Bull team boss Christian Horner has already admitted could be an 'option' - said he still had no firm news about his future plans but revealed that the decision over the next step in his career would be a tough one to take.

"I still don't have an answer for what will happen next year, it hasn't changed since the last two races," he was quoted by experienced F1 journalist Adam Cooper. "Obviously people will be talking more about chances but it doesn't really change what I will do next year or what my decisions are, even if there is obviously an open place.

"I have no contract, which is normal in F1. I have nothing to tell people unless there is something certain on paper, and then I will tell immediately because for me it's much easier, everybody stops asking the same question. Until I have something I can't answer.

"I think whatever the decision will be will not be an easy one. It's never easy. It's not the first time that there are different options on the table, then you take the one that you thing is right for you at the moment. It's hard to say if it's the right or wrong decision, but then you have to live with it, whatever it is."

Vettel himself has hinted that he wouldn't have a problem with having Raikkonen as his team-mate next year, being quoted by the British press as quipping that 'nobody would have a problem with Kimi as team-mate, expect for Perez' in reference to the clash between Raikkonen and McLaren's Sergio Perez during the Monaco Grand Prix.