The transformation into green transportation is a new opportunity for Hong Kong to expand its market in developing electric vehicles.

That's according to Secretary for Environment and Ecology, Tse Chin-wan, who told a radio programme that while many countries and regions are promoting green transportation, not many places have double-decker buses.

The authorities earlier announced a green transformation roadmap of public buses and taxis, with plans to subsidise the purchase of electric buses and taxis.

The environment chief stressed that it's worth investing as Hong Kong can make use of the advantage and expand its market in the technology that's involved.

"This green transformation actually provides opportunities under the establishment of a new economy... If we use subsidies to help double-decker buses develop the technology, we can grasp the opportunity," he said.

"Hong Kong is an international city and we can set an example for other places."

The government shelved the pay-as-you-throw scheme earlier this year, and though some green groups say the scheme should still be rolled out at some point, Tse noted that the authorities would continue to promote waste reduction and recycling rates.

He added that there are different means to do so, but the ultimate aim is to establish a green-focused culture in society.