A desperate rescue effort is underway in Taiwan, with dozens of people believed to be trapped in road tunnels after the island was hit by its biggest earthquake in 25 years.

Nine people are so far confirmed dead and more than 1000 injured in Wednesday’s 7.2 magnitude tremor, which was centred in the mountainous, sparsely populated county of Hualien.

Taiwan’s fire department said put the total number of missing people at 52, including 38 hotel workers.

The disaster management command centre said the search for the hotel workers on their way to Taroko Gorge, a national park, was a major focus. Authorities planned to send in drones and helicopters to look for them and drop supplies if they are located.

Others who had been trapped are gradually being found and taken to safety.

On Thursday, a helicopter rescued six people who had been trapped in a mining area, the fire department said.

In Hualien, some buildings tilted at precarious angles after the quake triggered massive landslides.

Linda Chen, 48, said her former apartment in downtown Hualien city was so badly damaged in a 2018 earthquake that she and her family had to move. On Wednesday, her new apartment was also damaged.

“We worry the house could collapse anytime. We thought we had already experienced it once in Hualien and it would not hit us again, because God has to be fair,” she said.

“We are frightened. We are so nervous.”

The quake hit at a depth of 15.5 kilometres, just as people were headed for work and school.

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

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

A woman who runs a bed-and-breakfast in Hualien city said she scrambled to calm her guests who were scared by the quake.

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

Some buildings are tilted at precarious angles in Hualien after a magnitude 7.2 earthquake. Photo: AAP

The government put the number of injured at 946.

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

The rail link to the area was expected to re-open on Thursday, Lai, who is set to take office next month, told reporters.

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

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.

Aftershocks could still be felt in Taipei, with more than 50 recorded, weather officials said.

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

The official Central News Agency said the quake was the biggest since one of magnitude 7.6 in 1999 that killed about 2400 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.

-with AAP