Cape Town - Sebastian Vettel and Ferrari are believed to be at loggerheads over the German's new contract, according to Finnish newspaper Ilta Sanomat.
Vettel is out of contract at the end of this season, but Ferrari have put a lucrative three-year deal on the table for the four-time World Champion.
However, Ilta Sanomat claim they have sources that believe Vettel is holding out for a new one-year deal instead in order to keep his options for 2019, when Lewis Hamilton's contract with Mercedes expires.
Vettel was quizzed about his future ahead of the Hungarian Grand Prix, with certain sections of the press suggesting he is delaying his decision.
The German insisted, though, there was no issue between himself and Ferrari, and that contract talks would wait until the summer break.
Ferrari boss Sergio Marchionne has all-but confirmed that they will announce their driver line-up for 2018 at their home grand prix in Monza in early September.