Transport Commissioner Rosanna Law on Saturday rejected suggestions from the taxi industry that the government should consider waiving the HK$120 fee for driver cards under the new electronic toll payment system, saying it's not a good use of taxpayer money.

Speaking after a television programme, Law stressed that other than paying for a physical tag, taxi drivers could use the HKeToll for nothing by logging on to their account online or through the app.

She said the government is considering public feedback over the new system.

"Hong Kong has 18,000 taxis, and around 40,000 active cabbies, but more than 200,000 people with a taxi-driving licence. If we give everyone [with a licence] a [free] driver card, it won't be in line with the principle of making the best use of public money," she said.

She also said it might not be a good idea to not give a card to cabbies who only rarely drive taxis.

The HKeToll system was meant to make its debut at the Tsing Sha Control Area on February 26, but the launch has been pushed back to May 7 after the government received complaints from motorists and lawmakers.

Law added that drivers without a tag using tunnels where it's installed could pay the toll within 14 days.