Strong winds knocked down people and scattered debris as a massive typhoon crossed over Taiwan on Tuesday, killing at least four people and injuring more than 260, officials said.

Typhoon Megi's bands of heavy rain and sustained winds of 162 km/h blanketed the island by midafternoon as the eye of the storm made landfall on the east coast. Authorities had raised alert levels for Taiwan, which is prone to landslides and flooding, said National Fire Agency Director-General Chen Wen-lung.

The 268 injuries included eight Japanese tourists travelling in a tour bus that turned on its side in central Taiwan. Three people suffered fatal falls and a fourth person died in a truck crash, said Lee Wei-sen, a spokesman for Taiwan's Central Emergency Operations Center. Many of the injuries were from falling and wind-blown objects.

Megi is 500 kilometres in diameter, and rainfall had topped 300 millimetres in the south and eastern mountains.

APTOPIX Taiwan Typhoon

A woman eats and struggles with her umbrella against powerful gusts of wind generated by typhoon Megi across the the island in Taipei, Taiwan on Tuesday. (Chiang Ying-ying/Associated Press)

"The rainfall problem will get increasingly severe as the storm passes over," Lee said. "We've got to see whether the amount of rain has a big impact. The only good news is that it's moving fast on its way over Taiwan."

More than 8,000 people had been evacuated, mostly from mountainous areas at risk of landslides or floods. About 2,800 went to shelters, Chen said.

Power knocked out

More than 2.9 million households lost power, though 976,000 had been restored by late evening, according to Taiwan's Central News Agency.

More than 121 flights were delayed and 253 cancelled at Taoyuan International Airport, and seven were diverted to other Taiwanese airports. Authorities had closed schools, offices and most of Taiwan's railway system.

Megi is the fourth typhoon of the year to hit Taiwan.

On the Chinese coast, about 160 kilometres from Taiwan at its nearest point, fishing boats were ordered back to port, China's official Xinhua News Agency said. It said the typhoon was expected to reach Guangdong province and Fujian province Wednesday morning, bringing as much as 400 millimetres of rain to parts of Fujian.