Toto Wolff has admitted that Sebastian Vettel's work ethic may have helped Ferrari to speed ahead in 2017.

In recent days, conspiracy theories have circulated hinting at collusion between Italy's Ferrari and Pirelli, as the 2017 Ferrari is notably better at finding the narrow operating tyre 'window'.

Pirelli hit back, saying that Vettel has simply worked harder than Mercedes's Lewis Hamilton.

"Each driver has his own way to prepare," team chief Toto Wolff is quoted as saying by Speed Week.

"One wants to be perfect and is a meticulous worker, while the other relies more on his instinct.

"Sebastian was always a worker, so perhaps he understood earlier on how to get the tyre in the right working window. We have to catch up now."

Wolff admitted that the Mercedes car is also to blame.

"Our car is difficult to set up," he said, "particularly when it comes to getting the tyres to work optimally. But we know what we are lacking."

What might also be lacking in forthcoming races is motivation within Hamilton, who according to some experts can become quickly demoralised.

"On the contrary," Wolff insisted. "Lewis is not a problem but rather a positive influence, and I see him wanting it more than he did last year.

"Also for the team as a whole there will be no problem in this regard."

Vettel currently leads Hamilton at the top of the standings by 25 points.