Mercedes boss Toto Wolff believes Ferrari has dedicated a lot of its resource this year to an assault on the title in 2017.

Ferrari's challenge to Mercedes has faded as the season has progressed, but with big regulation changes looming this winter each team has had to decide how to divide resources between 2016 and 2017. Wolff thinks Ferrari may have toned down its development of its current car to use its wind tunnel time and CFD capacity to develop next year's challenger.

"No, I don't think you can write Ferrari off, they have clearly had a tough time most recently," Wolff said when asked if he thought Mercedes and Red Bull would be the teams to beat in 2017. "I think they [Ferrari] switched off [2016 development] very early to focus on 2017.

"Never underestimate a team with so much resources and so much passion."

Wolff said it is important for Formula One to have close competition at the front of the grid after he expectedmore of a challenge from Ferrari this year.

"We need to be fair sportsmen and Formula One lives because of the great battles between drivers and teams. Ferrari is a great brand with capable people and it would have been good fun to fight it out on track. For whatever reason they have not been able in the most recent races to reach the levels they expected to perform and we expect to perform, but I can't really look into it in detail and I don't know the reasons.

"For me, a battle with Ferrari would be great for F1 and, even if this sounds a little bit absurd, I was really looking forward to it and I hope they find their strength again and we fight it out on track."