Cash-for-Clunkers program, which has so far helped in boosting the auto-sales, has also lifted the prices of comparatively low-cost second-hand cars.

Cash-for-Clunkers program absorbed around 690,000 used cars from the market, making the supply short against demand. The poor customers will be hit the most due to increased prices of the used cars.

The smaller number of used cars in the market will also affect the auto-parts market, which basically depends on older cars.

Greg Peeples, Leigh Automotive Mercedes-Benz dealership's general manager, said, "Prices are up, and there is definitely a shortage of used cars."

On the other hand, less than 20 per cent of applications from auto-dealers for repayment have been endorsed so far.

The Obama administration said it would add additional workforce of 2,000 people in the existing workforce of 3,000 people to accomplish the task fast.

Under the cash-for-clunkers program, rebates worth around $2.8 billion are claimed by the dealers.