The automotive industry is relying on special deals such as 'fleet sales' to rental car companies in order to bolster sales that are masking the severity of the fall in demand according to industry analysts.

R.L. Polk, a Michigan-based research company, claims that during the first three months of 2003, fleet customers recorded almost one in five of every new vehicle registered in the US.

With some individual companies such as Mitsubish, fleet sales accounted for as much as 42.6 per cent of total American sales.

Observers say that the Polk data points to a weakening of consumer demand in which the entire industry is likely to be badly hit.

Whereas in the early 1990s manufacturers were able to sell daily rental fleets to major operators such as Hertz, Avis and Budget, the room for growth in the car rental market has now dwindled.

The rental industry has become too weak to expand significantly as a result of the problems suffered by the travel industry, leading Bob Schnorbus, an analyst for J.D. Power and Associates to predict a difficult period for the industry.