Typhoon Chan-hom has crossed China's heavily populated eastern coast, forcing the evacuation of almost 1 million people, shutting transport links and devastating swathes of farmland, the government and state media said.

The powerful storm could be the strongest typhoon to strike Zhejiang province, just south of Shanghai, since 1949, China's National Meteorological Centre (NMC) said.

It made landfall at 4:40pm (6:40pm AEST) near the port of Ningbo, home to almost 6 million people, before brushing Shanghai and its population of 23 million.

Later in the evening, the storm slowed in speed and was packing winds of up to 162 kilometres per hour as it hit the city of Zhoushan, the NMC said.

Out at sea, Chan-hom was whipping up waves of up to 10 metres high, the US government's Joint Typhoon Warning Centre said.

Zhejiang evacuated about 960,000 people and called its entire fishing fleet back to port, state media said. Provincial authorities said earlier that nearly 30,000 vessels had moored safely.

Some parts of the province were deluged with more than 300 millimetres of rain in the 24 hours before Saturday morning, the local government said.

Shanghai forecast the typhoon would "brush" within 100 kilometres of the city late on Saturday or early on Sunday as it veered into the Yellow Sea, according to a local government posting on its official microblog.

The local government urged residents to stay home and cancelled several public events as rain picked up towards midday.

"We recommend everyone does their best to use 'squatting at home' tactics to welcome the typhoon," it said in a statement.

Shanghai's Pudong International Airport cancelled 500 flights while Hongqiao Airport cancelled 250 because of the typhoon, the official People's Daily newspaper said.

Typhoon Chan-hom (centre left) lashes Japan's Okinawa island chain as it pushed towards Taiwan and onto China. ( AFP: Japan Meteorological Agency )

Chan-hom is forecast to affect a wide swathe of China, also bringing heavy rain to the eastern provinces of Fujian and Jiangsu, the NMC said.

Fujian province, south of Zhejiang, has evacuated more than 30,000 people and Jiangsu another 10,000 people.

People in coastal fishing farms in Fujian were asked to evacuate on Friday morning when the NMC first issued a red alert — the highest level — for the former super typhoon.

The storm left five people dead in the Philippines earlier in the week and injured more than 20 people in Japan on Friday as strong winds uprooted trees and battered buildings, the Tokyo Broadcasting System reported.

Four people were also injured by falling trees in Taiwan when the storm buffeted the island on Friday.

"The upcoming typhoon seems very powerful. We have sealed all our windows and doors and have stored food," said Liu Yimin, a villager in coastal Huagang village, according to Xinhua.

Apart from the closure of schools and the suspension of flights and trains, more than 51,000 ships had returned to port, local authorities said.

The typhoon is the second storm to hit China in two days after severe tropical storm Linfa made landfall on the coast of southern Guangdong province.

Hot on the heels of Chan-hom, Typhoon Nangka is swelling over the Pacific Ocean and is expected to travel north-west towards Japan's Ryukyu Islands in the coming days.

The Japan Meteorological Agency described the intensity of the storm as "very strong".

Authorities in Zhejiang said the province may face $421.66 million in economic losses, with agriculture the worst affected, a local news agency reported.

Huge waves dwarfed six-storey buildings as Typhoon Chan-hom approached Wenling in Zhejiang province on Friday. ( AFP )

AFP/Reuters