Strongest earthquake in 25 years rocks Taiwan, killing nine people ...

Rescuers are working to free dozens of people trapped after the strongest earthquake in a quarter-century rocked Taiwan on Wednesday morning, causing landslides and collapsed buildings. 

The earthquake killed nine and injured more than 900, while 50 workers travelling in minibuses to a hotel in a national park were missing.

The government put the number of injured at 946.

Some buildings tilted at precarious angles in the mountainous, sparsely populated county of Hualien, near the epicentre of the quake, which struck just offshore at about 8am local time.

Taiwan’s earthquake monitoring agency said the quake was magnitude-7.2 while the US Geological Survey put it at 7.4. 

The earthquake has led to collapsed buildings and landslides. (Reuters: Walid Berrazeg)

As darkness fell, some people were spending the night in tents and other shelters.

Meanwhile, scores of emergency workers were trying to shore up damaged buildings and demolish those deemed impossible to save.

"The Uranus building behind us is a very badly damaged place. It is a building with one basement level and nine floors above ground. The first and second floors are now underground," Deputy Acting Chief of Hualien Fire Department Lee Lung-Sheng said.

People evacuated from their homes sit outside a shelter after the main earthquake in Hualien City in eastern Taiwan.(AP Photo: Chiang Ying-ying)

Australia's Labor MP Tania Lawrence is now stuck in Taipei in a hotel lobby following the earthquake during a private visit to Taiwan.

Ms Lawrence said she felt "extremely violent" shakes from a hotel room on the 9th floor, as well as "very frequent aftershocks". 

There is no other option other than staying in the hotel, she said. 

More than 50 aftershocks were recorded, Taiwan's weather officials said.

"I'm afraid of aftershocks, and I don't know how bad the shaking will be," a 52-year-old Hualien resident, who gave her family name as Yu, said as she made her way to a shelter.

The power of the quake was captured live as news anchors delivered their breakfast bulletins, steadying themselves against giant screens as their sets swayed and lighting rigs rocked back and forth overhead.

The earthquake hit at a depth of 15.5 kilometres, as people were headed for work and school, setting off a tsunami warning for southern Japan and the Philippines that was later lifted.

Video showed rescuers using ladders to help trapped people out of windows.

Fire authorities said they had already evacuated some 70 people trapped in tunnels near Hualien city, including two Germans.

But they had lost contact with 50 workers aboard four minibuses heading to a hotel in a national park, Taroko Gorge, they said, and rescuers were looking for them.

Another 80 people are trapped in a mining area, though it was not immediately clear if they were inside a mine.

On a highway through the mountains, huge boulders from a landslide were strewn across the road.

The Fire Bureau of Taichung City Government said it rescued a man in his 50s who was unconscious in a truck.

"At present the most important thing, the top priority, is to rescue people," said President-elect Lai Ching-te, speaking outside one of the collapsed buildings in Hualien.

Hualien city Mayor Hsu Chen-Wei said all residents and businesses in buildings that were in a dangerous state had been evacuated.

Forty-eight residential buildings were damaged in the city and demolition work was beginning on four buildings, the mayor said. 

A woman who runs bed-and-breakfast accommodation in Hualien city said she scrambled to calm her guests.

"This is the biggest earthquake I have ever experienced," said the woman, who asked to be identified only by her family name, Chan.

Taiwan is regularly jolted by quakes and its population is among the best prepared for them.

But authorities expected a relatively mild earthquake and did not send out alerts.

"I've grown accustomed to (earthquakes). But today was the first time I was scared to tears by an earthquake," said Hsien-hsuen Keng, a resident who lives in a fifth-floor apartment in Taipei.

"I was awakened by the earthquake. I had never felt such intense shaking before."

Workers carry out demolition operations near some collapsed buildings. (Reuters: Walid Berrazeg)

The White House said the United States stood ready to provide any assistance necessary.

Taiwan's air force said six F-16 fighter jets had been slightly damaged at a major base in the city from which jets are often scrambled to see off incursions by China's air force, but the aircraft are expected to return to service very soon.

In Japan, the weather agency put the quake's magnitude at 7.7, saying several small tsunami waves reached parts of the southern prefecture of Okinawa, while downgrading its tsunami warning to an advisory.

In the Philippines, seismology officials warned coastal residents in several provinces to move to higher ground.

Chinese state media said the quake was felt in the south-eastern province of Fujian, while a Reuters witness said it was also felt in the commercial hub of Shanghai.

Most power has been restored after the quake, electricity utility Taipower said, with the island's two nuclear power stations unaffected.

Taiwan's high-speed rail operator said no damage or injuries were reported on its trains, although services would be delayed as it made inspections.

Strong tremors in Taipei forced the subway system to close briefly, although most lines resumed service.

The official central news agency said the quake was the biggest since a magnitude-7.6 in 1999 that killed about 2,400 people and damaged or destroyed 50,000 buildings.

Taiwan weather officials ranked Wednesday's quake in Hualien as "Upper 6", or the second-highest level of intensity on a scale ranging from 1 to 7.

Such quakes collapse walls unless they are made of reinforced concrete blocks, while people cannot stand upright and must crawl in order to move, experts say.

ABC/Wires