Formula One title contender Kimi Raikkonen says his McLaren needs to be more powerful as well as more reliable if he is to win the championship this season.

"I guess we need more horsepower but it is not so easy to find," Britain's Autosport magazine quoted the Finn as saying on Thursday.

"I am sure we are not at a level where BMW (Williams) or some others are at the moment but first we have to try to get (the engine) to be reliable," added last year's overall runner-up.

Raikkonen challenged Ferrari's Michael Schumacher for the title last year, losing out by two points after a showdown at the final race in Japan as the German won his record sixth championship.

The Finn could still become the sport's youngest champion this year, with Formula One supremo Bernie Ecclestone already tipping him for the title.

Mercedes-powered McLaren start the season with a new car but have only rarely stood out in testing so far. Raikkonen said he was confident that the recent problems in Barcelona would be sorted out.

"We know the reasons we didn't go well there so hopefully we can improve," he said. "There is still work to do on the car but at least it seems to be more reliable now, so hopefully we can improve on the speed."