Businessman Alan Ng, 45, left his gold Kia Carens overnight near his office along Upper Thomson Road on Monday.

When he came back at about 9.30am the following day, he found the six-year-old car in floodwater as high as the wheels.

He finally had the car towed to the Independent Damage Assessment Centre yesterday afternoon, where it is to be assessed so he can lodge a claim with his insurance company, NTUC Income.

'In the morning, the water was still a foot high,' he said. 'Water had got into the engine, and soaked the leather seats. I was shocked because you don't see such things very often in Singapore.'

Motorists such as Mr Ng bore the brunt of heavy rains and flooding this week.

At least four workshops The Straits Times checked with logged a 10 to 20 per cent increase in the number of vehicles booked for repairs this week.

Most were in for minor damage, including dented boots, broken headlamps and smashed windscreens. Most were a result of vehicles colliding in the rain, they said.

Mr David Tai, operations manager of Huat Heng Motor Trading, which is handling nine vehicles damaged in the floods, said: 'Only a few were serious ones, like the whole front damaged. In those cases, all the destroyed parts must be changed.'

Depending on the age and model of car and extent of damage, motorists have to cough up from a few hundred dollars to fix a dent or scratch, to as much as $10,000 to change vehicle parts.

Another workshop, A & C Autocare in Sin Ming Drive, received 20 to 25 damaged cars and vans in the past week - 10 per cent more than in the same period last year.

Most motorists will get their insurance companies to foot the bill, but some prefer to settle in private to avoid increasing their premiums in the future, said Hock Wah Motor Workshop, which is handling close to 20 accident claim cases after the floods.

'The insurance premium is higher this year, so most owners opt for private settlement and repair by themselves,' said manager Evelyn Ong.

NTUC Income, which has 140,000 private car policy holders, said payouts depend on the severity of the damage.

A simple cleaning up of the upholstery costs about $3,000 to $5,000. If the engine is affected and needs to be overhauled, the repair cost can be in the region of $10,000, said a spokesman.

'So far, we have received two claims as a result of yesterday's flooding,' she added.

Mr Kei Takasaku, a vice-president at American Home Assurance Company, which has 160,000 motor insurance policy holders, said it is assessing just one flood case currently.

'It's not serious damage. When floods occur, at least in Singapore, it's not like the cars are completely flooded to the roof,' he said. 'It's more like water seeping in from the door, or water getting into the engines and causing short circuits in the electronics.'