A Telegram chat group, set up about two weeks ago to facilitate motorbike pooling services, has garnered more than 2,000 members despite its stringent criteria.
But it is an illegal move, as motorists are not allowed to ferry passengers for hire and reward, the Land Transport Authority (LTA) said yesterday.
LTA also said motorcyclists who offer hitch-a-ride services may have their motorbike's insurance coverage declared void.
It added: "For their own safety, we strongly encourage commuters to use taxis or licensed private-hire cars for point-to-point transport."
Checks by The Straits Times found that the group was started on Oct 4. It had more than 2,500 members as of noon last Wednesday.
But after the group's administrators removed and banned members who did not display a photo of themselves, the numbers fell. As of yesterday evening, the group had around 2,080 members.
In its latest message to the group yesterday, an administrator again warned that privatised Telegram accounts without a display picture would be banned from the group. Users are also automatically greeted with a message on the rules.
One rule is that any damages arising from any transactions will be borne by the rider and pillion rider.
In a message last week, the group administrators warned members not to mention that monetary reward was involved if they are stopped for checks during their trips.
Those who fail to comply with the rules will be banned from the group. They can get the ban lifted by paying a $30 fee, which they can do only once.
Mr Lim Biow Chuan, a member of the Government Parliamentary Committee for Transport, said: "Not all motorbike riders can take a pillion rider because they may not have the experience. Motorbike sharing for commercial purposes is also likely to breach insurance policy."
If a pillion rider is injured or killed in an accident, there may be limited recourse for damages because the insurance will be denied, he added.
"Why would anyone take that risk?"