An urban planning specialist on Monday welcomed news that the government is carrying out a feasibility study on improving the road network on Lantau, but said the administration must be clear on its intentions for the project.

Paul Zimmerman, CEO of Designing Hong Kong, made the comments a day after Secretary for Development Bernadette Linn revealed that work began earlier this month to look at ways to better connect the north and south of the island.

Speaking on RTHK's Hong Kong Today programme, Zimmerman said the roads were difficult to navigate at the moment. But he said the authorities need to have a clear idea of what capacity they were building for, as improvement works could have a significant impact on the surrounding slopes and vegetation.

"We have to keep in mind that, if you're going to touch that road, it's going to impact the slopes," he told RTHK's Janice Wong. "The slope stabilisation along those roads has not been upgraded to the latest standards, so any work that's going to be undertaken will probably have an impact on the vegetation around it, and that's a real concern."

Noting that the minister had emphasised that the work would have a focus on conservation, Zimmerman said the question was whether the work could be concluded "in a nice and good way".

"Can they make sure that the road remains scenic, that we're not going to have large noise barriers, lack of planting and so on, so I think that is a real concern," Zimmerman said.

Writing on her official blog on Sunday, Linn said the Sustainable Lantau Office (SLO) under the Civil Engineering and Development Department would spend two years on the feasibility study.

She said officials would expand segments of several roads, such as South Lantau Road, Keung Shan Road and Tai O Road, in stages by way of minor works projects. They will also look into using the Old Tung Chung Road again.

Linn stressed the idea is to promote sustainable development of Lantau by conserving the south while developing the northern part of the island.