An "East Lantau Metropolis" could rise from the sea between Hong Kong and Lantau islands over the next 50 years, with the government looking at the possibility of reclaiming more than 1,000 hectares of land, government sources said.
One said the new metropolis would be similar in size to the city's airport island.
A real estate adviser said it could house outlet malls.
The sources made clear the scale of the plan after Chief Executive Leung Chun-ying unveiled the idea in his speech. He said: "It will become a core business district in addition to Central and Kowloon East for promoting economic development and providing job opportunities."
A government source said the new metropolis would be in a strategic location, and able to be connected by bridges or tunnels with Western District on Hong Kong Island, Lantau Island and parts of the western New Territories such as Tuen Mun.
The source said the Development Bureau would start a feasibility study by June, to be completed by 2017.
To prepare an economic and social development strategy for Lantau, Leung said he would establish a Lantau Development Advisory Committee.
The committee will also seek advice on ways to revive the Lantau development plan, drafted in 2007. Steered by Secretary for Development Paul Chan Mo-po, it will include representatives from the commercial and recreational sectors, planning and architectural fields, district councillors and lawmakers.
Leung said Lantau would become an essential connecting point for journeys to and from Hong Kong, Zhuhai and Macau when the 55-kilometre Hong Kong-Zhuhai-Macau bridge opens in 2016 and the nine-kilometre Tuen Mun-Chek Lap Kok link opens two years later.
"[Lantau] will link Hong Kong Island, Kowloon, the New Territories and the western Pearl River Delta, and become the converging point of traffic from Guangdong, Hong Kong and Macau," he said. "This will bring fundamental change to [its] functions and development potential."
Vincent Cheung Kiu-cho, national director at real estate firm Cushman & Wakefield, said the plan should focus on retail development instead of luring companies to set up office there.
"The reclaimed area will have a great potential for retail development, which will be the primary beneficiary of the opening of the Hong Kong-Zhuhai-Macau bridge," he said. "Building American-style outlet malls will be an ideal operation model to lure shoppers."
- The Development Bureau said reclamation for the bridge's border control point will be completed next year.