The world's longest sea bridge that will connect Hong Kong, Macau and the Chinese mainland will open to traffic on Wednesday.
The project, which has been surrounded in secrecy during construction, will have a grand opening on Tuesday in Zhuhai on mainland China - possibly attended by China's President Xi Jinping
Hong Kong MPs have criticised a lack of transparency over when traffic will be able to use the bridge, while local bus companies have also complained about being kept in the dark.
The 55-kilometre crossing, which includes a snaking road bridge and a tunnel that plunges into the sea, links Hong Kong's Lantau island to Zhuhai and Macau, across the waters of the Pearl River Estuary.
Construction of the massive infrastructure project began in 2009 and has been dogged by delays, budget overruns, corruption prosecutions and the deaths of construction workers.
Supporters of the bridge promote it as an engineering marvel, while others see it as a costly political project designed to further integrate Hong Kong into the mainland.