A mega-bridge connecting Hong Kong, Macau and the mainland Chinese city of Zhuhai officially opened Tuesday, with Chinese President Xi Jinping overseeing the event to showcase China's ambition to develop a regional economic zone in its southern coastal area.

Vice premiers Han Zheng and Liu He and government leaders and lawmakers from Guangdong Province, Hong Kong and Macau were among hundreds of guests at an opening ceremony in Zhuhai.

[Photo courtesy of Hong Kong Government]

"I announce that the Hong Kong-Zhuhai-Macau Bridge is officially open," Xi said at the event.

Han in his remarks said the 55-kilometer bridge-cum-tunnel across the Pearl River estuary "will facilitate exchanges of people between the three places, economic and trade development, boost competitiveness for the Pearl River Delta region and help integrate Hong Kong and Macau into the country."

Following the event, Xi and his entourage took a ride on the bridge toward Hong Kong and visited a manmade island, state media Xinhua News Agency reported.

Xi complimented the project on showing the country's comprehensive capabilities and the nation's ambition and for "strengthening our confidence in the theoretical system of socialism with Chinese characteristics."

He also hailed its essential role in developing the Greater Bay Area, a scheme to link Hong Kong, Macau and nine cities of Guangdong Province into an integrated economic and business hub.

The mega-bridge, for which construction started in 2009, will be opened to the public Wednesday.

Limited cross-border bus and shuttle bus services will be available to begin with, and private vehicles will need permits to travel on it.

What is being billed as the world's longest bridge-and-tunnel sea crossing will put the three cities within an hour's drive of each other.

It would only take around 45 minutes to travel from Hong Kong International Airport to Zhuhai, compared with around four hours now, and the traveling time between Zhuhai and Hong Kong's Kwai Tsing Container Terminal will be shortened from 3.5 hours to around 75 minutes.

The construction cost for the main body of the bridge, built to last 120 years, was around 15.7 billion yuan (US$2.3 billion), to be shared among the governments of Hong Kong, Macau and mainland China. But Hong Kong has invested HK$120 billion (US$15.3 billion) for its share as well as peripheral facilities.

Along with Guangzhou-Shenzhen-Hong Kong high-speed rail link, for which the Hong Kong section began operation last month, the mega-bridge "will greatly enhance the flow of people and goods between Hong Kong and cities within the Greater Bay Area like Macau, Zhuhai, Zhongshan and Jiangmen, help turn Hong Kong's role from a 'connector' to a 'partner'," Hong Kong leader Carrie Lam said.

Macau leader Fernando Chui said the bridge "serves to compensate the inaccessibility of land transportation between Hong Kong, Macau and the western Pearl River Delta region" and will be of strategic importance for economic cooperation.