Fourteen people have died in Taiwan's eastern county of Hualien, with 124 missing after a barrier lake in the mountains overflowed to deluge a town during a typhoon, the fire department said on Wednesday.

Taiwan has been lashed since Monday by the outer rim of Super Typhoon Ragasa, now heading for China's southern coast and the Asian financial hub of Hong Kong.

The barrier lake, formed by landslides triggered by earlier heavy rain in the island's sparsely populated east, burst its banks on Tuesday afternoon to send a wall of water into the township of Guangfu.