F1's two powerhouses, McLaren and Ferrari, have admitted that it could be weeks before they can match the pace of the Brawn GP cars.

Of last year's top three in the Championship, Lewis Hamilton, Felipe Massa and Kimi Raikkonen, only the latter was able to get within half a second of the pace set by Brawn GP's Jenson Button during Sunday's grand prix. Hamilton and Massa, in fact, were both a full second behind the Brit.

Brawn, though, have a head start on their rivals as, even though they entered this year's as a new outfit, they the former Honda team, who gave up on last year's Championship early in the season to focus their attention on this year's car, giving them a sizeable head start on the competition.

And that paid dividends on Sunday afternoon when the team stormed to the 1-2 in Australia with Button leading home Rubens Barrichello, while Hamilton finished in third place.

"Frankly, it will take a number of weeks to catch the Brawn car, which is a consequence of 16 months' investment from Honda to build a car. We have a lot of work to do to catch up," said McLaren team boss Martin Whitmarsh.

And he isn't the only one at McLaren who believes that the team faces a tough challenge bringing the car up to speed with Brawn's.

"In going to Malaysia there will be a bigger difference between us and the Brawn cars. We'll be further behind," said Hamilton.

"It's going to be even harder for us because the car is incredibly tough to drive, probably the hardest I've ever had to drive.

"Malaysia is more dependent on downforce and aero, so I think there will be a bigger gap, but hopefully by China (a fortnight later), and from then on, we'll be a little closer."

Hamilton's main rivals last season, Massa, is also expecting a bleak period ahead after he was even further behind the Brawns than the defending Champion. Added to his lack of pace, the Ferrari driver was also hit with a reliability issue that put him out of the grand prix.

"We need to improve very quickly the car," Massa said. "But in my experience when we see a car that is one second in front, to improve one second from one day to another is very difficult.

"I don't know if it is possible. When you are three or four tenths behind it is always possible, but if it is a second then it is quite difficult."

But despite admitting that Brawn could pull away in the standings over the course of the next few races, Massa adds that there is still a long way to go before the titles are decided.

"The Championship is still in the beginning and we know in Formula 1 that many things can change," he told Autosport.

"We have to keep our feet on the car and work hard, maybe the next track can be better for us with more temperature in the tyres and more grip as well. So I hope the car can behave better in Malaysia than here."

Team-mate Kimi Raikkonen is another who is not yet ready to award the title to Brawn, saying: "It is only one race, so let's see what happens."

The Finn also made mention of the upcoming Court of Appeal hearing into Brawn, Toyota and Williams cars, which could yet change the outcome of the Australian race - and in fact the performance of those three teams' cars throughout the rest of the season.

"We will see how is it in the next race," the 2007 World Champ said. "It all depends on the rules, what the rules are going to be in the future, there are a lot of question marks about what you are allowed to do and what not. So let's wait and see."