US vehicle sales are now stable at low levels but could improve slightly in the fourth quarter, Hyundai Motor's top US executive has said.

"It is remarkable how stable the market has been between 9.5 and 10m units this year," chief executive John Krafcik told Reuters.

He said there was growing evidence of pent-up demand: "If you look at people who say they are going to buy in the next six months, that number is increasing month over month in a pretty big way."

Krafcik also said the recently approved 'cash for clunkers' scrappage programme - passed by Congress last week - that would give US consumers up to US$4,500 to trade up out of older and less fuel efficient cars should boost the market.

"We think that's going to get more and more people thinking about jumping into the market," he told the news agency.

Automakers reported sales of nearly 10m vehicles on an annualised basis in May, a better result than most economists had expected the troubled US sector to achieve.

May saw the highest sales rate so far this year and industry executives have suggested that was an early sign the US market could be pulling out of its steepest slump since the early 1970s.

The first quarter sales rate was just 9.5m units.

Krafcik told Reuters US sales could rise past 10m units in the fourth quarter.

"As long as the economy has these green shoots and these little bits of sunshine, we do see some possibility for it to grow beyond the 10m unit level," he said.

Fear of job losses and volatile petrol prices were currently holding consumers back from buying cars, Krafcik added.

Hyundai's US sales for the first five months of 2009 were down 7.9% percent to 166,743, according to WardsAuto.com.