Typhoon Kong-rey was packing wind speeds of 184 kilometres an hour (114 miles per hour) when it slammed into eastern Taiwan on Thursday, uprooting trees, triggering floods and landslides, and knocking out power as it swept over the island.

A 48-year-old motorcyclist was killed by a falling power pole in the capital Taipei on Thursday, taking the storm's death toll to two, with more than 500 injured, the National Fire Agency said.

A search was also underway for four people who went hunting in the mountains of central Taiwan on Wednesday and have not been heard from since that evening.

Two Czech hikers who were trapped in the Taroko Gorge in Hualien county during the typhoon were rescued on Friday.

Kong-rey weakened to a severe tropical storm as it moved across the Taiwan Strait towards China on Friday, the Central Weather Administration said.

In Taiwan, life was returning to normal, with offices, restaurants and schools reopening.

But nearly 100,000 households were still without power and 191 domestic and international flights were cancelled.

Dozens of ferry services and some train lines remained suspended.

"The typhoon was so strong yesterday," Pan Li-chu told AFP at her restaurant in Taipei, where the awning had been bent by the wind.

- Mud and rocks -

Kong-rey dumped more than a metre of water in some of the hardest-hit areas along the east coast, the Central Weather Administration said.

Torrential rain in Toucheng town, in Yilan county, sent mud and debris flowing down the street and into a building in Wu Hsuan-kai's backyard.

Wu said he was watching television on Thursday morning when he heard a strange "rumbling sound".

"When I opened the door, I saw a mudslide coming down slowly. I picked up my car key and rushed out," Wu, 55, told AFP.

In Taitung county, where the storm made landfall, a fire department official told AFP there had been no reports of "severe damage".

"It's mostly trees falling down and crushing into electricity poles that caused a power outage," said the official, who gave only his surname Huang.

"There are four reported cases of flooding and all have receded. There are also three reported cases of mudslides, including one near a tunnel, which we are verifying now."

Further north in Hualien county, some residents living in the mountains were assessing the damage to houses hit by landslides.

"There are mud, small rocks, big rocks and driftwood -- I don't know where they came from," a resident in Zhuoxi village told local news channel TVBS.

"I can't go inside (my home). In some houses the mudslides are more than waist-high, it's a little better in my home which is below the knees."

- Model workers -

Across the island, workers were up before dawn clearing trees, branches and other debris from roads.

"We started cleaning from 5:00 am till now and have only cleaned one road section. It took us about two and a half hours," Lee Chia-hsin, a member of the New Taipei City cleaning crew, told AFP.

In the southern city of Kaohsiung, Australian firefighter calendar models visiting for a charity event put on high-visibility vests to help clear debris.

"Happy and proud that we could come out and assist your crews and give back to the Taiwanese people," one of the firefighters told local media.

Forecasters had warned of a severe impact from Kong-rey as it intensified into a super typhoon during its approach to Taiwan.

More than 11,500 people fled their homes.

Kong-rey was the same strength as Typhoon Gaemi, which was the most powerful storm to hit Taiwan in eight years when it made landfall in July, but Kong-rey's radius of 320 kilometres made it the biggest in nearly three decades.

Taiwan is accustomed to frequent tropical storms from July to October, but the weather agency said it was unusual for such a powerful typhoon to hit this late in the year.

Scientists have warned climate change is increasing the intensity of storms, leading to heavier rains, flash floods and stronger gusts.