The warning was issued by the Disaster Prevention and Mitigation Department.

Chatchai Promlert, the department’s director-general, said the influence of a strong southwest monsoon over the Andaman Sea and a low-pressure ridge over upper Vietnam would trigger heavy rains in the six provinces.

He said residents of the eastern provinces of Rayong, Chanthaburi and Trat and southern provinces on the west coast – Ranong, Phang Nga and Phuket – should prepare for heavy rains and possible flooding in some areas.

He said affected people could call 1784 around the clock to seek help.