Car manufacturers in the US say they believe that rising gas prices could help fuel demand for diesel cars in a similar fashion to the increase in interest in gasoline-electric hybrids.

US president George Bush has declared that he wants diesel-power passenger vehicles to receive tax breaks similar to those offered to owners of gas-electric hybrid vehicles.

And with diesels using 20 to 40 per cent less fuel than comparable gasoline engines, the economic incentive to consumers is growing.

DaimlerChrysler has already announced that 60,000 consumers have indicated early interest in the diesel version of its Jeep Liberty SUV and the company predicts it will make 5,000 vehicles this year, producing more if demand remains strong.

Meanwhile, Volkswagen is in the process of rolling out a diesel version of its new Jetta and BMW, Honda and Subaru are working on diesels that could go on sale in the US in the next few years, according to USA Today.

More than 12 per cent of Volkswagen's US sales were diesel versions of four models last year and DaimlerChrysler began offering a diesel Mercedes-Benz E320 CDI last year.

Elsewhere Ford Motor and the US Environmental Protection Agency are working together on a new project to create an extremely low-emissions diesel engine.

A Kelley Blue Book/Harris Interactive poll in March found that just a third of car shoppers surveyed said they would be willing to consider a diesel, while 65 per cent of respondents said they would consider a hybrid.