A US politician is pushing forward a scrappage proposal but wants it to only apply to US-built vehicles.

Betty Sutton's "fleet modernization bill" comes months after a previous scrappage plan failed in Congress when the United Auto Workers union incredibly objected.

At that time, UAW officials feared scrappage would subsidise foreign-made cars, despite the obvious equal benefits for their domestic brands.

This time, the UAW is backing Sutton's plan, which proposes vouchers of up to $5,000 for motorists trading in old vehicles for more fuel efficient new ones built in the US (the minimum qualifying is a 27mpg average consumption).

A smaller allowance would be given for new cars built in Canada or Mexico, and no discount for cars built overseas, even though they are generally more fuel efficient than US-built vehicles.

US motor analysts point out that the bill would exclude 28% of vehicles on sale in the USA, and would discriminate against dealers representing non-US brands.