But government inaction risked potential visitors abandoning the island for nearby Hengqin or Macau, which can be reached within half an hour after the bridge is completed, So said.

Better co-ordination of Lantau businesses - including exhibition venue AsiaWorld-Expo, Hong Kong Disneyland and the Ngong Ping 360 cable car - could contribute an additional HK$3 billion to HK$4.5 billion in revenue within a year, assuming visitors stay longer on Lantau and spend more.

That economic benefit could rise to HK$100 billion over a period of 10 years if more companies were attracted to set up businesses on the island, So argued.

Lantau lags far behind Hengqin and Macau in terms of commercial space and hotel room numbers, said the Lantau Development Alliance.

Hengqin plans to develop 11 million square metres of commercial area in its central business district and to provide 15,000 hotel rooms. Macau will have 50,000 hotel rooms by 2020.

Lantau has only 3,000 hotel rooms and 120,000 square metres of commercial space, the alliance's Allen Ha said.

"Now it's almost 2014 and there are only two years to go before the bridge is finished. If we still hesitate, we will lose out in the race," Ha said.

Separately, Secretary for Development Paul Chan Mo-po informed lawmakers of plans to develop 150 hectares of land on Lantau for immigration control and commercial facilities.

A passenger terminal building will provide restaurants, duty-free shops and other facilities.

The government is conducting the Tung Chung New Town Development Extension Study with the aim of developing the area into a bigger new town.