World champion Sebastian Vettel says Red Bull is unlikely to dominate Formula One this year in the way it has in the past two seasons.

And with the season-opening Australian Grand Prix two weeks away, F1 team bosses agree, saying test results point to a more even competition.

The German team-mate of Mark Webber admitted Red Bull was still searching for grip levels it had last year given the change in exhaust regulations for this season.

He said the top teams would be on a more even footing but a trend would not emerge until the second round in Malaysia.

“The biggest difference is that the cars have less grip, which will make us slower than last year,” Vettel told F1.com.

“Last season the way we incorporated the exhaust was very cleverly devised.

“It made the car faster by generating more grip, but it’s a thing of the past in 2012 and for now we have to live with it.”

Vettel said Red Bull’s grip level last year was “something you probably wouldn’t even dare to dream of.”

McLaren managing director Jonathon Neale said no one can be certain who is quickest.

“With number of world championship drivers we have and the competitive pace from teams so far, we should have a first quarter that is really close,” Neale said.

Mercedes boss Norbert Haug said the team had had “quite a good start” during testing but he could only guess at how competitive the car would be.

McLaren driver Jenson Button is upbeat about the season, saying “I’m the happiest I’ve ever been. I’m in a great place at the moment.”

“We haven’t quite won the world title in the last two years but I have won quite a few races with this team and I feel our time is coming,” Button said.