Transport officials say they have come up with a way to help stop people dumping cars they no longer want in alleys and at the side of roads, by plugging a loophole that lets owners off the hook if they stop renewing a vehicle's licence.

At present, a vehicle's registration is automatically cancelled if it hasn't had a valid licence for two years. The person whose name the vehicle is registered under can then no longer be held liable for anything related to it.

"Some irresponsible owners take advantage of this arrangement and abandon their unwanted vehicles on public roads and public back alleys, causing environmental hygiene and congestion issues," the Transport and Logistics Bureau says in a paper to Legco.

To address the matter, the bureau is proposing an amendment to road traffic regulations which would scrap the automatic cancelling of a vehicle's registration and instead enable officials to send owners a notice after two years, giving them three months to either renew their licence or take action to de-register the vehicle themselves.

Options for de-registration include having the vehicle scrapped, or shipping it out of Hong Kong.

The bureau is proposing fines of up to HK$10,000 and prison terms of up to three months for people who ignore the notices, with a subsequent conviction for the same offence leading to fines of up to HK$25,000 and jail terms as long as six months.

If the fines go unpaid, the authorities would refuse to issue or renew the offender's driving licence or to license any vehicle in their name.

The bureau said a commencement date for the proposed new offence is expected to be fixed by notice in the Gazette in the fourth quarter of next year.

Wesley Wan, honorary life president of the Hong Kong Automobile Association, told RTHK he welcomes the proposed changes, saying they could put a stop to vehicles being dumped.

"They will impose a penalty which is more expensive than scrapping the car. So I think that's a good way to avoid people abandoning a car after the licence expires," he said.

Lawmaker Gary Zhang said he thinks there should be exemptions in some cases.

"If a situation doesn't really involve illegal abandonment, for example, some car owners may simply not renew their registration due to personal reasons, or they don't plan to drive any more, or just park in their garage, I think the government shouldn't interfere too much," he said.