The Hong Kong-Zhuhai-Macao Bridge, which is expected to come into service this year, will not only open a window for cities on the western bank of the Pearl River estuary to access the global market but will facilitate the establishment of a world-class airport cluster, promoting the development of the Guangdong-Hong Kong-Macao Greater Bay Area, experts say.

The Bay Area consists of Hong Kong, Macao and nine cities in Guangdong province - Shenzhen, Guangzhou, Zhuhai, Dongguan, Huizhou, Foshan, Zhongshan, Jiangmen and Zhaoqing.

Many of the mainland cities on the river's western bank have limited communication with Hong Kong, Macao and international markets because of an underdeveloped transportation network. Consequently, the development of those cities has lagged behind those on the east bank.

The situation is expected to change when the bridge is completed. Traveling time between Zhongshan and Hong Kong, for example, will be reduced from 180 minutes to 105 minutes.

"As transportation between Hong Kong and cities on the western bank becomes more convenient, their interaction will become more active," said Guo Wanda, executive vice-president of the China Development Institute, a think tank based in Shenzhen. "This will help them better enjoy Hong Kong's advantages in finance and professional services, and its link to the outside world.

"Meanwhile, compared with Shenzhen and Guangzhou, those cities have lower land prices and wider spaces for development. More people may choose to invest there."

Mao Yanhua, deputy director of Sun Yat-sen University's Institute for Free Trade Zone Research in Guangzhou, said that with the bridge, cities in the Bay Area can benefit from economies of scale.

But the most serious issue that could affect the megaproject's impact is coordination. Systems at the three points of the bridge - for example, the way they handle border crossings - are different, Mao said.

Some industry insiders also believe the opening of the bridge will have a positive effect on regional airports, which are becoming increasingly important as more people move to the region.

Chen Xiaoning, secretary-general of the China Civil Airports Association, wrote in a report that the Bay Area will develop into a world-class economy, and thus requires a corresponding world-class airport cluster.

Currently, development of airports in the area is unbalanced, Chen said, noting that close cooperation is needed to achieve a win-win outcome.

As one of the busiest airports in the world, Hong Kong International Airport performed at historical highs in passenger volume, flight movements and cargo throughput last year.

It is building a third runway to expand its capacity, but construction will take at least seven years.

Luo Zhiyu, an aviation industry analyst, expects Macao International Airport will take spillover from Hong Kong.

Upon the completion of the cross-border bridge, travel time from Macao International Airport to Hong Kong International will be reduced from an hour by boat to about 20 minutes by road.

Meanwhile, travel time will be reduced from Hong Kong International to Zhuhai Airport, which has said it expects to act as Hong Kong's additional runway. Some airlines are already adjusting by distributing resources to the Macao and Zhuhai airports.

Macao International Airport statistics show passenger traffic at a historic high last year, while the passenger volume at Zhuhai surged from 799,000 in 2006 to 6.13 million last year - an average annual growth rate of 66.7 percent.

In April, the Guangdong government released a five-year plan for the province's transportation system. It calls for Zhuhai airport to expand its service from domestic routes to the Southeast Asia region, especially in freight transportation.