The 23-year-old German's current contract runs out at the end of this season, and he has indicated that if he cannot be promised a winning car for 2010, he will move on.

Sir Frank Williams on Tuesday revealed that his Grove based team will attempt to retain Nico Rosberg beyond 2009.

The 23-year-old German's current contract runs out at the end of this season, and he has indicated that if he cannot be promised a winning car for 2010, he will move on.

"For me it's a crucial year," Rosberg, who has repeated several times this winter the message that he is prepared to leave Williams if the next car is not a winner, said recently.

Rosberg entered formula one under Williams' wing in 2006, but he is adamant the time is right if necessary to exchange patience for a top cockpit.

"I understand that Mercedes would like a German driver and Nico is at the end of his contract this year," team boss and co-owner Sir Frank is quoted as saying by the Daily Express.

"We will be sitting down to talk to him sooner rather than later. We would most certainly like to keep him."

Toyota-powered independent Williams is keen to use the opportunity of sweeping rule changes this year to leap up the grid, but Rosberg warned in the Daily Telegraph: "This is the one big chance that Williams are going to get.

"If we don't get it right now we don't deserve to get it right."