Facilities such as waste collection points and electricity substations could move underground to free up space at ground level, an engineer involved in a study on development beneath the city said.
Chief Executive Leung Chun-ying announced in January that the study would be undertaken "with a view to increasing usable space and enhancing connectivity in the urban areas".
Public debate focused on the possibility of vast underground shopping malls in the four areas Leung identified: Causeway Bay, Happy Valley, Tsim Sha Tsui West and Admiralty-Wan Chai. But Dr Samuel Ng Kwok-choi, chief geotechnical engineer for the Civil Engineering and Development Department, said yesterday that commercial development was only one possibility.
"Not only commercial uses, but car parks, transport hubs or even cultural facilities and amenities may be located in new underground spaces," Ng told an Eastern District Council meeting. "We can move down things which we don't want to see on the ground, such as refuse collection points and power substations. By doing this we can free up more above-ground spaces."
Sites covering more than 200 hectares have been identified, Ng said, though their suitability for underground development had not yet been studied.
Council member Chan Kai-yuen, an engineer, supported underground development, but said not all uses were suitable.
"These districts are already densely developed. Building more shops there will overload them," Chan said. "Instead, it would be good to relocate shops below ground and free up space above for community facilities."
Victoria Park, Hong Kong Stadium and the Happy Valley Racecourse are among the sites identified as possible locations for underground development.
The administration plans to ask lawmakers for HK$60 million in funding in June. The study would begin later this year and end in late 2016 or early 2017.