General Motors has said it hopes to have a marketable hydrogen fuel cell vehicle by as early as 2010.

Issuing a progress report on the US company's research into hydrogen technology, vice president Larry Burns said that GM had signed a four-year $10 million contract with a government lab to achieve its goal.

The Sandia National Laboratory in California is currently working with GM to develop a hydrogen fuel tank for cars.

"We're looking to literally reinvent the automobile," said Mr Burns.

Scientists are developing a method to store hydrogen in a fuel tank by using compounds known as complex metal hydrides that can absorb and release hydrogen. The metal hydride system will allow more power to be stored in the same size tank than more popular compressed air systems.

"Our goal is to squeeze as much hydrogen energy as possible into the same space we devote to petroleum fuel tanks," said Chris Moen, manager of Sandia's science and engineering technology department.

By sharing its latest research efforts, GM officials hope to demonstrate that the company is making progress on the key technological challenge of storing hydrogen, a low-density gas that must be converted into a denser form to be stored on-board a vehicle.

GM has said it can power a hydrogen car at a cost of about $500 per kilowatt, but it estimates that it needs to lower the cost to $50 per kilowatt in order to make it cheap enough to be mass-produced.