The launch ceremony was hastily announced last week by mainland authorities with Hong Kong lawmakers and transport companies complaining they had been left in the dark.

Supporters of the project promote it as an engineering marvel that will also boost business and cut travel time, while others see it as a politically driven costly white elephant.

The main bridge section is considered mainland territory and Hong Kong cars and drivers travelling over it "must comply with the laws and regulations of the mainland", according to the city's transport department.

Hong Kong residents will only be granted a licence to cross into Zhuhai if they meet highly selective criteria, including holding certain mainland government positions or making major contributions to charities in the southern Chinese province of Guangdong.

Most people will need to travel the bridge on coaches and buses.

Online commenters in Hong Kong complained about the bridge's restricted access ahead of the launch.

"Such a huge investment using the Hong Kong taxpayer's money ... yet basically it is not open to us at all," said one comment on the South China Morning Post website.

Some Hong Kong media reported that the physical condition of drivers would be monitored by cameras, including an alert sent if a driver yawns more than three times in 20 seconds.

Data such as a driver's heart rate and blood pressure would also be collected through wearable devices and sent to the control centre.

The opening of the high-speed rail link also sparked criticism as it saw Chinese security stationed on Hong Kong soil for the first time at the city's terminus.

Critics accused the Hong Kong government of giving away territory to an increasingly assertive Beijing.