A veteran town planner and member of the chief executive's think tank has questioned the need for a new town proposed at the border.
Peter Cookson Smith - who planned satellite towns including Sha Tin, Tai Po, Sheung Shui and Fanling - said it was not clear what purpose the new town, planned for the northern New Territories, would serve.
"How long might the border be there?" the president of the Institute of Planners and member of the Commission on Strategic Development asked. "Things are really happening in the Pearl River Delta at the moment."
Cookson Smith's questions - raised in an interview with the South China Morning Post - arose from measures announced in Chief Executive Leung Chun-ying's policy address to build up the government's land reserve and tackle an acute housing shortage.
The proposals include rezoning government, institute and community sites for residential use and developing a "modern new town" that faces Shenzhen.
Cookson Smith, who was appointed in January to the commission, chaired by Leung, said past efforts indicated that the city lacked direction and strategies for making living space less crowded.
He said he hoped the commission, which will hold its first meeting next month, would "define the way forward for the city in a thoughtful way".
Cookson Smith said he had mixed feelings about Leung's maiden policy address, delivered two months ago.
Plans were announced to build flats on sites originally designated for schools and open space. Planning officials were also asked to increase development density.
"Building a land bank is right," the veteran planner said. "But we shouldn't fill every spare site with high-rises."
He said a high-speed cross-border rail link, due for completion in 2015, would change the commuting style between the city and the mainland.
For example, Hongkongers would be able to travel from West Kowloon to areas such as Nansha - a new commercial, technology and educational hub under rapid development in Guangzhou - in about 30 minutes.
"Retired people could live up there in Nansha and go back to Hong Kong twice a week with the high-speed train," he said. People would be able to return to the urban area without having to check in at the Shenzhen-Hong Kong border.
Cookson Smith, who is involved in the planning of Nansha, said the Guangzhou government had emphasised quality of life in the area, building more than 5,000 hectares of artificial wetland and miles of boardwalk.
"All are beautifully done," he said.
On the other hand, he said, Hong Kong was now emphasising quantity in building flats, although it had made many efforts in the past 20 years to reduce development density.
"You can't simply go on intensifying developments and building shoebox units at that kind of level. It was okay 30 years ago when we built new towns as people really didn't have accommodation. Now we really have to look at the quality," he said.
Cookson Smith warned against building another Tseung Kwan O - the most densely populated new town with an average of 2,500 people per hectare.
Instead of adding density in urban areas, he urged the government to review its small-house policy and use land reserved for such houses to build flats instead.
He said he had advised the government in the 1980s to provide proper planning and infrastructure for small houses.
"If the government had adopted our advice, the New Territories would be very different today," he said.