A strong earthquake hit Taiwan on Sunday, leaving two dead, one missing and 21 others injured, officials said.

The quake, which violently shook buildings in the capital Taipei, sent people running into the streets and was also felt in Hong Kong, more than 700 kilometres (435 miles) away.

Taiwan's Seismology Centre measured the quake's magnitude at 6.3, while the US Geological Survey put it at 6.2.

The tremor hit at 1:43 pm (0543 GMT), centred 32 kilometres east of the central county of Nantou at a depth of 10 kilometres, followed by a series of aftershocks, the Seismology Centre said.

The National Fire Agency said a mountain climber was killed after he was hit by falling rocks on Mount Ali in central Taiwan, while the second victim also died after being knocked down by falling rocks.

In Chushan town of Nantou county, rescuers were running against time, digging through tonnes of rubble which buried a male angler.

"The rescuers have been working hard to search and rescue the missing person, even though, I'm afraid, the odds of finding him alive is slim," a National Fire Agency official told AFP.

Twenty-one people were injured, including three severely, the agency said.

TV footage showed widespread landslides, stirring clouds of yellow dust, on other mountains in the area.

Comprehensive cracks were seen on the walls of the houses and highways there, they said.

TV stations also reported that panic-stricken shoppers were seen running out of a 12-storey department store in the central city of Taichung.

The fire agency told AFP that four helicopters had been sent to scout the area around the epicentre as authorities waited for any further damage information.

Six high-speed trains were halted but services resumed after no damage was found to the line.

More than 20,000 travellers were affected as 54 railway trains were delayed after the quake, the Taiwan Railways Administration said.

Operations at the three nuclear power plants on the island were not affected, according to state-owned Taiwan Power Co.

"This is the biggest earthquake to hit this year. As the origin of the quake was shallow and it happened in the centre of the island, its velocity could be felt islandwide," Lu Pei-ling, deputy chief of the seismology centre, told reporters.

"Today's earthquake was somewhat related to the 1999 one."

Nantou county was the epicentre of a 7.6-magnitude quake in September 21, 1999 that killed around 2,400 people in the deadliest natural disaster in the island's recent history.

In late March, a strong earthquake in the same vicinity as Sunday's tremor killed one person and injured 86 others. Violent shock waves damaged buildings and triggered two blazes.

Taiwan lies near the junction of two tectonic plates and is regularly hit by earthquakes.