Hong Kong has played a vital role as trade gateway in the Pearl River Delta's development over the past two decades. It has facilitated fast, efficient movement of the region's export goods out of China to all parts of the globe, and has become the world's busiest container port.

But as the PRD's economy develops, Hong Kong's role is changing. "The most important point in this respect is the degree of co-operation over infrastructure between Hong Kong and nearby cities in the PRD region," says Gilles Guiheux, a researcher at the Hong Kong-based French Centre for Research on Contemporary China.

Ground transport plans are already well advanced. Work should start this year on building a new highway, the Shenzhen Western Corridor, linking the west side of Hong Kong with the Shekou port district in the Shenzhen Special Economic Zone via a 5.4-kilometre (3.4 mile) bridge.

A new cross-border rail link, the 7.4-kilometre (4.6 mile) Lok Ma Chau spur line, is scheduled for completion in 2007. This will offer a second rail border crossing to relieve congestion at the existing crossing at Lo Wu.

Authorities on the Guangdong side of the border are meanwhile looking to accelerate the development of their transport infrastructure. The Guangzhou-Shenzhen superhighway, built by Hong Kong construction company Hopewell, has been operating for nearly 10 years. Now the rail links are up for renewal.

The train journey between Shenzhen and Guangzhou now takes around 90 minutes. The goal, announced earlier this year, is to reduce this to 30 minutes with an elevated light railway.

Hong Kong International Airport already has the world's biggest freight through-flow. Now the aim is to link its cargo facilities more directly with the transport network of the Pearl River Delta.

"The essential goal of the Airport Authority is to look for ways of integration with the region," says Chris Donnolley, a spokesman for the authority. This means finding ways of co-operating rather than competing with the delta region's four other airports, at Shenzhen, Guangzhou, Zhuhai and Macau. The preferred way, Mr Donnolley suggests, would be to link Hong Kong's international routes into the Chinese domestic networks.

The airport currently has a marine cargo terminal carrying goods to and from some 20 ports, mainly on the western side of the Pearl River. Now it is considering setting up a logistics centre on Nansha Island, half way up the Pearl River between Hong Kong and Guangzhou, from where cargo could be moved to Hong Kong airport aboard high-speed ferries.

The additions to Hong Kong's cross-border road and rail networks, combined with the ability of the airport to reach directly into the heart of the Pearl River Delta, will allow the SAR to maintain its position as south China's trade services and logistics base.