Lewis Hamilton's winning streak at Mercedes has become a turn-off for Formula One fans according to former world champion Sebastian Vettel.

Vettel, who has also been accused of turning viewers away from the sport after he won four consecutive championships with Red Bull between 2010 and 2013, said F1 is too complicated.

Mercedes have dominated the sport for the past two seasons, winning  32 of the last 38 races.

With very few changes to the regulations over the winter they will head into the new campaign as the favourites.

But Vettel believes their incredible run of success, as well as the sport's complicated rules and quieter engines, has forced fans away.

"The dominance of Mercedes in the past two years took away a lot of excitement for the fans," said Vettel.

"The new rules focus too much on details. Today the car plays an important role, like it did in the past, but we shouldn't get lost in overcomplicated rules.

"Our audience has to be able to identify with our cars again. At the moment F1 is just too complex and we're lacking sound.

"I think we have to be careful not to lose the roots of motor racing and I certainly hope the cars of the future will be more within their grasp."

Vettel (above), who won three races last season after making the switch from Red Bull to Ferrari, will hope to take the challenge to Hamilton when the season gets under way in Melbourne next month.

But the German's comments will do little to allay fears that the sport could be in for a repeat of last season's uninspiring championship which Hamilton largely dominated.

Vettel's remarks emerged as Toto Wolff, the Mercedes boss who has overseen his team's rise to the very top of grand prix racing, urged those involved in F1 to be more positive.

"I have read once that the most successful species is the one that is able to adapt itself most quickly and this is about Formula One, this is how Formula One functions,” Wolff said.

"So there are threats that we know today but there are ones that we don't know and they will appear tomorrow, so we just need to be aware that everything is possible in Formula One.

"In terms of the sport itself I think we need to stop talking ourselves down. This is important as there is some great news around the sport."

The season-opening Australian Grand Prix takes place on March 20 while the first of two four-day winter tests gets under way in Barcelona next Monday.