Over 80% of newly registered minibuses are LPG-powered, Secretary for Environment, Transport & Works Dr Sarah Liao says.

Since the introduction of the LPG and electric minibus incentive programme, minibuses running on diesel now only constitute just over 10% of newly-registered light buses.

Dr Liao said she believed yet more owners will replace their diesel buses with LPG or electric ones.

Replying in the Legislative Council to Emily Lau's queries on the incentive programme today, Dr Liao denied that difficulties have been encountered in its implementation.

"We also do not consider it necessary at this stage to think of other options to achieve our aim to reduce emissions from light buses," she said.

Among the 6,000-odd diesel light buses in Hong Kong, about 400 have already been replaced by LPG ones.

Dr Liao said diesel vehicles have the highest emission levels, while LPG vehicles have the lowest and electric vehicles have none at all.

She said petrol vehicles generally have the highest operating costs per kilometre travelled, when only the retail prices of fuels and fuel efficiency are taken into account. Electric vehicles rank second, followed by diesel ones. LPG vehicles have the lowest operating costs.