Old Phuket town is among 49 places deemed vulnerable to flash floods or landslides in Phuket, the Mineral Resources Department said on Tuesday.

The department identified 49 "at-risk villages", including the old quarter and the Chartered Bank community, both popular sites in Muang district.

On Aug 23, heavy rain resulted in landslides that killed 13 people, injured 19 others and damaged more than 50 houses. Officials blamed the clearing of trees on Nak Koet hilltop to make way for a giant statue known as the Big Buddha.

With more heavy rain and rough seas forecast through Saturday, Phuket's governor has ordered all agencies to prepare for possible flash floods, runoff and landslides.

Meanwhile, the Chao Phraya Dam in Chai Nat province in the Central Plains has increased its water drainage rate to prepare for increasing rainfall in the North caused by Tropical Storm Yagi expected to hit Thailand on Friday. 

Water levels in 11 provinces in the Chao Phraya river basin, including Bangkok, are expected to rise by up to 40 centimetres.