The independent apps are not programmed by taxi operators and, thus, allows developers to unite bookings across several cab firms and enhance success rates.

For example, GrabTaxi, which was launched in mid-October, detects passengers' locations and scans the vicinity for drivers, using inbuilt maps on smartphones. GrabTaxi does not collect a booking fee from passengers during its current trial, which ends next month, but encourages commuters to tip drivers at their own preference.

A spokesman for the firm declined to reveal the take-up rate but said there was more than a sixfold increase in successful job allocations last month. During trials, The Straits Times, successfully booked a cab twice, out of four occasions.

The second app, MoobiTaxi, another free app, consolidates booking services by the different taxi firms on top of allowing passengers to 'check-in' to nearby locations and find drivers. More than 10,000 users have signed up for the service since September. Additional a limousine-booking service for premium customers is also in the works.

The third app, Cab-Pare, helps to calculate and compare taxi fares, which founder Wong Ling Jun, cited can go up to $20 for the same route. The app costs S$1.25 and was launched two weeks ago.

According to the local paper, The Land Transport Authority (LTA) revealed via a media statement that it does not regulate third party taxi apps, but is reviewing their impact.

Taxi operators, however have mixed responses. A spokesman for ComfortDelGro, said that the company would 'definitely consider' external apps that bring in more jobs for its drivers.

Yet, Prime Taxi's, Deputy General Manager, Neo Chee Yong, is worried such third party apps would greatly affect the company's booking hotline. "We acknowledge that such apps are innovative and useful but we have concerns about how it affects our quality-of-service results, since LTA regulates call centre service standards," he explained.