Analysts say that US car and light truck sales will rise by around four per cent during March, as the latest set of official production figures are about to be released.

Experts at General Motors say they are anticipating a rise equivalent to an annual rate of 16.7 million vehicles, slightly above Wall Street estimates.

Paul Ballew, GM's executive director of market and industry analysis, told Reuters: "We're seeing some sales momentum."

"We're starting to see the benefits of economic growth and tax refunds," he added.

Official figures will be released next Thursday but some analysts are less confident than Mr Ballew.

Merrill Lynch analyst John Casesa pointed to the impact of incentives, and also warned that there was much ground to be gained after a disappointing start to the year.

"Although the pace of sales appears to be picking up in March, it will need to start doing double time soon to reach full year expectations," he commented.

Meanwhile, Mr Ballew says GM remains confident that industry sales will ultimately strengthen to an annual rate of 17 million as the economy improves.