HUALIEN, Taiwan -- The number of people injured in a 7.2 magnitude earthquake in eastern Taiwan climbed past 1,000 on Thursday though the death toll remained steady at nine, with dozens of workers on their way to a hotel in a national park mostly now found safe.

The temblor, the strongest in 25 years, hit on Wednesday morning just as people were readying to go to work and school, centred on the largely rural and sparsely populated eastern county of Hualien.

Buildings also shook violently in capital Taipei, but damage and disruption there was minimal.

Taiwan's fire department said the number of injuries had reached 1,050, putting the total number of missing at 52. Around two dozen of almost 50 hotel workers on their way to a resort in Taroko National Park had been located.

The fire department said the group was trapped on the cross-island highway which traverses the gorge connecting Hualien with Taiwan's west coast and is a popular tourist destination.

It showed drone footage of some of the hotel workers, along with other people, waving from the side of a road, with the crushed back part of a minibus also clearly visible. Another group of 26 workers had also been found, it added.

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

The railway line to Hualien re-opened ahead of schedule on Thursday, although one rural station north of Hualien city remains closed due to damage, the railway administration said.

In Hualien city, where people who had been trapped in buildings have all been rescued, some people slept outdoors overnight as more than 300 aftershocks rocked the region, unnerving residents.

A lady, 52, who gave her family name as Yu, said she checked herself into a tent on a sports ground being used for temporary shelter late on Wednesday night because she was too scared to sleep in her apartment, which she described as "a mess".

"The aftershocks were terrifying. It's nonstop. I do not dare to sleep in the house," she said.