Singapore Land Transport Authority (LTA) has informed the ride-sharing firm, Grab, that the service model of its car-pooling service between Singapore and Johor Bahru "did not comply with regulations in Singapore", Channel NewsAsia reported Monday.

The report said, Grab is currently running a free pilot programme for their Singapore-Johor Bahru service, however, and LTA noted that such free cross-border car-pool rides are legal.

"Malaysian-registered cars are not allowed to provide hire-and-reward services in Singapore without a public service vehicle licence," a LTA spokesperson was quoted as saying.

"Likewise, Malaysian regulations do not permit Singapore registered cars to do the same in Malaysia without a public service vehicle licence."

The report said Grab had on June 13 announced and published fare estimates, putting the average cost of a trip at S$12 (S$1=RM3).

But on the weekend the service was due to launch, Grab reportedly said in its website that the service would be a three-week-long fare-free pilot programme.

It also stated that it is currently "engaging with the LTA in Singapore and regulatory authorities in Malaysia" on the use of car-pooling solutions to improve connectivity between Singapore and Johor Bahru.

The report said illegal paid cross-border ride-sharing services do exist in Singapore, and primarily advertise their services through applications such as Facebook and WeChat.

Under section 101 of the Road Traffic Act, any person caught using a foreign-registered motor vehicle as an unlicensed public service vehicle to convey passengers for hire and reward can be fined up to $3,000 and jailed up to six months, it said.