Industry representatives on Wednesday urged the government to keep prices to a minimum when it ends free charging for electric vehicles (EV) at its car parks.

In papers submitted to the Legislative Council, the Environmental Protection Department said self-service payment kiosks will be installed at several public car parks over the next few months, and it hopes the move will encourage more private car parks to provide charging services.

The government hasn't said how much it will cost to charge an electric vehicle at public car parks.

The chairman of Charged Hong Kong, Mark Webb-Johnson, said it has not been feasible for car parks to offer paid charging so far, as they would have to compete with free charging spots.

"The free charging is obviously a great incentive for the purchase and use of EVs, but the problem with free charging is it doesn't help an economy grow up around this," he told RTHK's Hong Kong Today programme on Wednesday.

"[Paid charging] also incentivises people to use the facilities properly. If something's free, it tends to be abused."

As for how much the government should charge at public car parks, Webb-Johnson said: "We need to make sure that the EVs are still cheaper to operate than the conventional petrol or diesel vehicles."

On another RTHK programme, DAB lawmaker Ben Chan suggested that the rate should be set at HK$2 per kilowatt-hour or "a unit of electricity".

"Since they are government-owned car parks, they should not be profit-oriented," Chan said. "I hope [the fee] will cover the cost, and does not need to draw from public money."

Ringo Lee, the president of the Hong Kong Automobile Association, told the same programme that officials should install faster charging stations.

He also called on the government to step up surveillance and require electric vehicle owners who don't move their cars once they are fully charged to pay extra.