Wolff remains wary of Ferrari threat for 2017

The Maranello squad started the year with the goal of winning races from the start to challenge Mercedes for the title, but has yet to score a victory in 2016 and has dropped behind Red Bull in the constructors' championship.

Apart from its on-track struggles, Ferrari also recently lost a key component of its technical staff, technical director James Allison.

But with Ferrari having focused early on its 2017 car design, Wolff reckons the team cannot be ruled out.

"I don't think you can write Ferrari off," said Wolff. "They have clearly had a tough time recently.

"They switched off very early for 2017, so never underestimate a team with so many resources and so much passion. That will be my view."

Wolff reckons Red Bull will also be back in full force next year thanks to the progress made by Renault with its engine.

"We were expecting Hungary to be a very difficult one and Red Bull to perform well, and it was the opposite," Wolff added.

"We were as strong as well as Silverstone, and Hockenheim should have been one easier for us and it happened not to be, so I think it is not clear cut.

"We haven't seen Lewis [Hamilton]'s real pace in the car because he managed the gap, but they keep coming back.

"There wasn't a lot of speed differential on the straight any more and sector three looked to be very good for Red Bull so they will be coming back in full form next year.

"We have kept it [the lead] for nearly two and a half years and it is not going to last forever."