"Daniel needs to make sure that he's comfortable and he's making the right decision for next year," Horner told Sky Sports.

"From our perspective, we've got plenty of options. Our desire is to continue with Daniel and, at the right moment in time, there'll be an opportune moment to sit down and discuss the future with him.

"It feels a bit early at this point in time."

Red Bull have been tipped to challenge for the constructors' championship this season, but Horner insists Mercedes – winners in each of the last four years – remain heavy favourites.

"It's so hard to draw conclusions – you get a bit of a flavour," he said. "Mercedes are in great shape, Ferrari are looking strong. We hope we're there or thereabouts.

"It'll be great for Formula One if there's a few teams in contention this year. But Mercedes are definitely going into this championship as very much the favourites."