World champion Lewis Hamilton's [Images] new McLaren [Images] is too slow and it could be some time before it can win races, the Formula One team said on Friday in a frank acknowledgment of their pre-season problems.

"There is a lack of downforce and we are currently working hard to solve this problem," Mercedes motorsport vice-president Norbert Haug said in an interview supplied by the team after their disappointing pace in testing this week.

"Basically, the car feels good -- that is what our drivers say. However, we are currently definitely not fast enough, not competitive enough to aim for victories.

"We are definitely not where we want to be," added the German. "We will continue our test programme next week at Jerez for another four days. But it will take time to improve."

World champion Hamilton was the slowest driver on track in Barcelona on Wednesday and was not much quicker on Thursday.

McLaren's woes were highlighted by the astonishing pace of the former Honda team, now Brawn GP, who are using the same Mercedes engine and were fastest on the last two days of their debut test.

AERO PROBLEM

Team principal Martin Whitmarsh, who took over from Ron Dennis at the start of the month, said there was an evident problem with the car's latest aerodynamic update and engineers were working flat out to fix it.

Formula One's regulations have had a major revamp this season with the most significant aerodynamic changes in more than a decade.

"Our Mercedes-Benz engine is strong, we saw that last year, so MP4-24's performance shortfall is clearly chassis-centric," said Whitmarsh, ruling out any problem with the new KERS energy recovery system.

"It is a car's aero aspect that confers the greatest pluses and minuses to its overall performance package, and that would appear to be the case with MP4-24."

Asked whether the car was fast enough, he replied: "Not at the moment -- and certainly not by our team's extremely high standards."

He added however that "many times in Formula One history have successful teams started off with a car that was not working as well as they had hoped it would, and many times have those successful teams engineered their way back to the front of the grid in impressively short order.

"That is what we aim to do. In fact, that is what we are already doing."

Haug, whose company owns 40 percent of McLaren, could not promise that the car would be up to speed by the season-opening race in Australia [Images] on March 29. Hamilton, whose team mate is Finland's Heikki Kovalainen [Images], won that race last year.

"We are working hard to improve. However, it might take us a few races to significantly improve," said Haug, who added that Mercedes' commitment to Formula One at a time of global economic crisis would not be weakened by a poor season.

"Our partnership has won three drivers' titles and one constructors' title so far, and we will be back fighting for more championships even if it takes some time this year," he said.

"We have demonstrated in the past that we can win against the strongest opposition and we will work very hard to prove this again."

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