Flights were disrupted, ferry services cut and at least 160,000 people have been evacuated as Typhoon Megi, one of the strongest storms to hit the region in years, headed Friday for southern China.
Megi -- which killed at least 36 people when it ripped across the Philippines and has left 20 Chinese nationals missing in Taiwan -- was expected to make landfall either late Friday or early Saturday in Fujian province.
So far authorities in Fujian have evacuated more than 150,000 people from low-lying areas, while 10,000 others have been moved to safer ground in Guangdong.
The State Oceanic Administration issued a yellow storm surge warning, saying waters could exceed the danger levels. Tens of thousands of fishing boats in Fujian and neighbouring Guangdong province were ordered back to port.
"The storm surge could be so devastating that buildings, docks, villages and cities could be destroyed by it," Xinhua news agency quoted Bai Yiping, a senior forecaster at the State Oceanic Administration as saying.
At 0300 GMT Friday the storm was located 290 kilometres from the border of Fujian and Guangdong provinces, moving at a speed of up to 10 kilometres an hour, according to China's national weather centre.
The storm was Friday packing maximum sustained winds of 173 kilometres an hour.
The administration and other government agencies have ordered local authorities to reinforce seawalls and protect fishing facilities, Xinhua said.
China Southern Airlines had already cancelled flights from the Guangdong provincial capital Guangzhou and Xiamen to the Philippines capital Manila, and said service would be further disrupted to Southeast Asian cities.
Domestic flights originating in Guangzhou were also affected, the China Daily said, citing airport sources.
Railway ferry services linking the mainland to the southern island of Hainan have been suspended through Saturday, and many coastal cities have also cut ferry services until the storm passes, the newspaper said.
Officials in Guangzhou have called on organisers of next month's Asian Games to do everything possible to protect venues for the sports event, the world's second-largest after the Olympics.
"The sports gala must open in Guangdong's provincial capital as scheduled on November 12," the China Daily quoted provincial vice-governor Li Ronggen as saying.
Megi will be the 13th typhoon to hit China this year, and is the strongest storm to hit the northwest Pacific in two decades, meteorologists say.
In Taiwan, 20 Chinese nationals and three Taiwanese were unaccounted for after their tourist buses were hit by torrential rains and mudslides, rescuers said.
In hard-hit northeastern Ilan county, flash flooding submerged streets and a railway and forced dozens of schools to shut down on Thursday. The central weather bureau warned more than a metre (three feet) of rain could fall.
In Hong Kong, some restaurants have offered to re-book wedding banquets, while residents stockpiled canned food, local media reported, even though forecasts suggested the city would escape the full force of the killer storm.
The Hong Kong Observatory however warned of possible flooding in low-lying areas, prompting emergency crews to lay sandbags in preparation.
On Thursday five oil terminals on Tsing Yi island off Hong Kong's Kowloon peninsula were shut down, forcing tankers to anchor offshore and suspending marine fuel deliveries.
China was hit earlier this year by its worst floods in more than a decade, with more than 4,300 people dead or missing -- including 1,500 people killed in one devastating mudslide in the northwestern province of Gansu in August.