Drivers caught will be slapped with a fine and imprisonment as the act threatens lives, said police spokesman Phillip Mah in a letter to The Straits Times.
The act is similar to using the mobile phone while driving, and so can result in a penalty of up to $1,000 (£361) or a jail term of up to six months, or both. Also, the convicted offender can be barred from driving vehicles of all types for up to half a year, he said.
Mah also said in the letter that using a mobile phone while on the road distracts motorists and reduces their ability to react to changes in the road and to control their vehicles.
He was replying to a letter from a reader who was in a bus where the driver, in full view of alarmed passengers, text messaged with one hand while driving with the other.
Several countries, including Singapore, fine drivers who use handheld phones behind the wheel. Drivers are instead advised to ask their passengers to make or receive calls on their behalf. Those who are alone can use a hands-free device, but are advised to keep conversations short.
Some localities are stricter: in the New York state, the use of handheld phones in cars was banned in 2001.
In the UK, from 1 December it will be an offence to drive while using a mobile phone.
