Motor racing-Ricciardo set for two more years at Red Bull - Reuters

"It's always been pretty discreet," the 26-year-old told reporters when asked at the European Grand Prix about his contract and recent comments from team bosses that he was committed long term.

"Helmut made a few comments perhaps...it's good. Obviously it means he likes me. It's hard to tell some days but I honestly think the team is very happy with the line-up they've got at the moment. I'd say it's pretty stable," he added.

Austrian Helmut Marko, consultant to the energy drink's billionaire owner Dietrich Mateschitz, told Germany's Auto Motor und Sport this week that "Ricciardo will be with us until 2018, there is no doubt."

Team principal Christian Horner also said the team planned to keep the same line-up beyond next year.

"Yes, but not just 2017," Horner told the formula1.com website last weekend when asked whether Ricciardo and 18-year-old Dutch driver Max Verstappen, who won in Spain last month on his debut for the team, would be staying.

Ricciardo has been linked in media speculation to Ferrari, who have Kimi Raikkonen out of contract at the end of the year. The Australian also has an Italian passport through his parentage.

Ricciardo and Ferrari's Sebastian Vettel were team mates at Red Bull in 2014.

"The contract was always long term and in a way it was always that length," Ricciardo told Sky Sports television.

"But it's performance based and obviously Helmut and the team are happy with what I am doing and happy with me and Max and want to keep us on board.