A refined housing and tourism development plan released yesterday would see Lamma Island's population almost double from 5,900 to nearly 11,000.
And about one-third of new residents would live in subsidised flats under the proposal.
The mixed housing development, at a 20-hectare former quarry along the northern coast of Sok Kwu Wan, would also feature a resort with a 260-room hotel and centres for water sports and outdoor recreation.
The plan, based on an option the planning department said was "well-received by the public" in the first round of consultation, would mean an extra 5,000 residents living in 1,900 flats, of which 700 would be subsidised. The previous plan called for 1,000 flats housing 2,800 residents.
While the Planning Department says the increase will justify providing more public facilities like a library and community health centre, the change has sparked criticism from a resident and a green group.
"The high-rises are incompatible with the natural landscape that is popular among nature-lovers. They could end up being luxury apartments targeted by speculators and left vacant," island resident Damon Wong Chun-pong said.
Chief Executive Leung Chun-ying has pledged to increase the number of subsidised flats built citywide from 5,000 to 8,000 a year. The public consultation on the Lamma development will enter its second stage tomorrow.
The department floated three options for the quarry site in the last round of consultation in December 2012. While two focused on housing - one with a population of up to 7,000 - the third option featured a marina and small-scale private housing.
In a paper submitted to the Town Planning Board yesterday, the marina was removed, while the existing five-hectare man-made lake and nine-hectare woodland are preserved.
Residential blocks would range from four to 13 storeys.
A new ferry pier would be built to accommodate the existing licensed ferry services serving Sok Kwu Wan and Mo Tat Wan.
The pier would be the major gathering hub for residents and visitors, featuring an open-air "Entrance Plaza" for festivals and a two-storey commercial block of 6,000 square metres.
Despite the intense development, no new gas main would be included in the near future. Residents would have to rely on LPG cylinders or electricity.
Wong said the proposed settlement meant 10 times the existing population - 500 residents - would be living on southern Lamma.
"The new development plus the new ferry service would put pressure on the southern part of the island, where a protected nesting site for green turtles is located," he said.
Conservancy Association campaign manager Peter Lee Siu-man said the new development would become another Discovery Bay on Lantau: "Lamma will become a small town but I can't see how it will benefit the local population."
Lee also questioned if people who could only afford subsidised flats were willing to move and live on the island.
The consultation will end on May 17.