Frome flyer Jenson Button says there is "more to come" from his McLaren car after continuing his pre-season testing at the Circuit de Catalunya on Saturday.

With the season starting at the Bahrain Grand Prix on March 14, Button believes that they are still not getting the most out of the car.

"The car is good but there is still room for improvement," he said.

"I'm reasonably happy with it. There's more to come. There are areas we know we were a little bit weak in but they are areas we can change with set-up.

"I'm happy with the car that we have but I don't think we're getting the maximum out of the package we have.

"If you look at the times – the long runs – the Ferrari is competitive – but we all knew that.

"Ferrari will be quick. Fernando (Alonso) will definitely be quick, as will Felipe (Massa). They are both very experienced drivers and very talented.

"They will get the best out of the car and we will do the same; we just haven't had enough time to get the best out of the package we used today."

After winning the world title with Brawn GP last year, Button will now race alongside fellow Briton Lewis Hamilton at McLaren.

And with Michael Schumacher returning to Formula 1 to race for the Mercedes team, there is plenty of anticipation for the 2010 season.

However, Button believes it is difficult to predict which teams will be making the running one the season gets under way, although he did suggest that Sauber might be the surprise package.

"I think the Sauber will surprise a few people," he said.

"I think it's quicker than most people think. I think they'll be up there at the first race.

"There could be five or six teams who could be competitive but it's all a bit of a guessing game at the moment and it will be until we qualify on Saturday in Bahrain.

"It's exciting and it's good for the sport and exciting for the fans and for all of us involved."