300,000 motorists have had requests for car loans rejected during the past six months, with young drivers being hit the hardest.
The research from financial website Moneyexpert.com reveals that around 1600 people a day have had loan requests turned down.
Drivers aged between 18 and 24 are twice as likely to face rejection than those aged over 35.
The news is especially worrying for the motor industry because, prior to the economic downturn, three out of four new cars were bought on credit.
Business Secretary Lord Mandelson is tomorrow expected to announce measures to increase the availability of credit to the motor industry's financial arms. It is hoped such a move will help stimulate new car sales, which dropped by over 21% in December alone, compared with the same period in 2007.