Former Chief Executive CY Leung said on Sunday that authorities should consider expanding a new cross-boundary travel scheme if its initial implementation proves successful.

By the end of the year, mainland motorists will be able to apply for the Southbound Travel for Guangdong Vehicles scheme.

Up to 100 vehicles per day will be permitted to access Hong Kong's urban areas.

Speaking on a TVB programme, Leung, who is a vice-chairman of the Chinese People's Political Consultative Conference, said while the starting quota is small, it represents significant progress.

"We can observe the situation. We can review it a few weeks after implementation. If it works, we can then allow more vehicles," he said.

"At the same time, I think we should also consider whether, in addition to allowing 100 vehicles into the urban areas, we could allow another batch of vehicles to move around Lantau Island, but that they would not be permitted to cross the Tsing Ma Bridge?

"After all, Lantau has more space. I believe this would further leverage the integration role of the Hong Kong-Zhuhai-Macau Bridge."

Leung also said differing holiday schedules between Hong Kong and the mainland present an opportunity. With Hong Kong's market often quieter during holiday periods, more Guangdong vehicles could potentially be accommodated under the scheme.

Meanwhile, participants in both the southbound and northbound travel schemes can only cross the border via the Hong Kong-Zhuhai-Macau Bridge at the moment.

Looking ahead, Leung suggested authorities consider opening other land ports and implementing a "co-location arrangement", which would allow travellers to complete customs and immigration procedures for both Hong Kong and the mainland at a single checkpoint.