Private-car hire drivers operating under Uber and GrabCar may soon be required to have a vocational licence, under regulations expected to be announced next month.

A proposed training programme lasting at least 10 hours - shorter than the 60-hour taxi driver vocational licence (TDVL) course - is being considered by the authorities for these private chauffeurs, sources told The Straits Times.

The licensing requirement, which follows a review that started last October, is expected to be announced by the Ministry of Transport next month during the Budget debate.

There will be a "phase-in" period to allow drivers time to go for the vocational course, said industry sources who requested anonymity. It is estimated that there are tens of thousands of private-car hire drivers here.

Course credits attained during the proposed vocational training could also be used for the TDVL, should the drivers want to become cabbies.

Besides vocational licensing, sources said, the authorities are mulling over clearer markings on cars being used to pick up passengers. This could be through decals pasted on these vehicles to identify them.

There will be a "phase-in" period to allow drivers time to go for the vocational course, said industry sources who requested anonymity. It is estimated that there are tens of thousands of private-car hire drivers in Singapore.

Asked about the upcoming regulations, the Land Transport Authority said only that it was finalising the review. "More details will be made known in the coming weeks," a spokesman said.

With a regulatory framework, Singapore will join other countries, such as the Philippines and Australia, which are moving towards regulating an industry that has come under heat worldwide for allegedly competing unfairly with taxis.

Transport Minister Khaw Boon Wan had said in October that, where justified, the Government would "level the playing field" between taxis and private-car hire services.

The head of Grab Singapore, Mr Lim Kell Jay, said vocational licensing can serve as an "added assurance" to commuters.

He said the company does its own screening in the form of "background checks, in-person registration, induction training as well as vehicle inspections".

Uber's general manager in Singapore, Mr Warren Tseng, said he was "hopeful of a positive outcome" to the review - one that will ensure drivers can continue to have flexible work opportunities, and commuters, reliable transportation options.

Private-car hire driver James Koh, 53, said if vocational licences become a requirement, part-timers may find it a hassle and stop driving. "We have been operating for so long without problems, I find it strange that we need to have a licence," he said.

However, National University of Singapore transport researcher Lee Der Horng said regulations actually benefit private-car hire services by legitimising them.

He said services like Uber and GrabCar should also disclose data on their platforms with the Government, as taxi operators do.

"The Government can have full visibility of how many vehicles are on the roads on a day-to-day basis, and how much mileage is clocked.

"By being better informed, policies can be adjusted to help solve transportation issues in Singapore, for example, by putting more taxis or private cars for hire on the roads."