The Chinese finance hub saw scores of fallen trees and flooding in multiple neighborhoods, with the storm surge smashing the glass doors of an upscale hotel and flooding its lobby, according to footage circulated online.

Ragasa is churning away from Hong Kong gradually around noon but the city will still be lashed by hurricane-force winds, according to the Hong Kong Observatory, which issued the highest level of typhoon warning overnight.

Ragasa has brought "significant storm surge", with waters at coastal areas rising more than three meters above the reference level, the observatory added.

The nearby casino hub of Macau -- which also saw widespread flooding -- has suspended power supply to some low-lying areas, according to utility company CEM.

In Taiwan, at least 14 people were killed and 18 injured when a decades-old lake barrier burst in the eastern Hualien county after Ragasa pounded the island, according to regional officials.

The super typhoon killed at least two people while ripping through the northern Philippines.

China's Ministry of Emergency Management said the typhoon is expected to make landfall along Guangdong's coast between Zhuhai and Zhanjiang from midday to late Wednesday.

Authorities across mainland China ordered businesses and schools to shut down in at least 10 cities across the nation's south, affecting tens of millions of people.

Streets were mostly empty as wind picked up on Wednesday morning in Yangjiang, a city west of Hong Kong near where the typhoon is expected to make landfall.

One local shopkeeper told AFP she was not sure if she would be able to open her convenience store today. "It will depend on the weather conditions," she said.

The Yangjiang train station -- normally bustling with activity, locals said -- stood empty, with rail travel suspended Wednesday across the province of Guangdong.

Multiple districts in Hong Kong saw instances of flooding, according to images circulated on social media and verified by AFP.

At the Fullerton Ocean Park Hotel, next to a theme park, a man was seen losing his balance after storm surge shattered the glass front doors and swept into its lobby, one of the videos showed.

"We are doing all we can to mitigate the impact brought about by the super typhoon," a spokesperson for the hotel told AFP.

Floodwaters rushed into the seaside Heng Fa Chuen residential estate and covered its interior courtyards, another video clip showed.

Strong winds ripped off the top of a pedestrian footbridge, while many of the city's tall buildings swayed and rattled in the harsh winds.

An off-duty firefighter surnamed Tse told AFP he was "a bit worried" about the safety of nearby bamboo scaffoldings as he walked home after an 11-hour shift of "non-stop" work.

"This one was forecast to be quite bad so we were expecting a bit of chaos... (but) everywhere seems to be functioning quite efficiently still," said 27-year-old chef Benjamin Phizacklea.

Rail operator MTR said train services on open sections were suspended, with limited service available on the underground sections.

Authorities said more than 760 people sought refuge at the 50 temporary shelters across Hong Kong.

The city' airport operator said "only a limited number of cargo flights" were scheduled for Wednesday, with its website listing hundreds of cancelled passenger flights.

A five-year-old boy and his mother fell into the sea on Tuesday afternoon while they were watching the waves in the Chai Wan district, according to police. Both were in critical condition after they were rushed to hospital.

The boy's 40-year-old father, who reportedly jumped into the water to save his family, was also hospitalized.