Two more people have been found dead in eastern Taiwan, raising to 12 the number of fatalities in the strongest earthquake to hit the island in 25 years.

Authorities on Friday discovered two bodies on a hiking trail in quake-ravaged Hualien County.

Rescuers also found more survivors, including nine from a winding cave known as the Tunnel of Nine Turns, which is popular with tourists.

More than a dozen people were still unaccounted for and about 700 others were trapped, with roads blocked off by landslides and rockfalls in the quake-hit areas, authorities said.

Hundreds of aftershocks have been reported since Wednesday's 7.3-magnitude tremor that left more than 1,000 injured.

And authorities on Friday began tearing down the Tien Wang Hsing, or Uranus, Building in Hualien City, which tilted at a 45-degree angle after the quake.

Demolition work is expected to last about a week. (Agencies)