The weather office said Durian, a typhoon that lashed Vietnam and the Philippines, had weakened to a depression, while Surat Thani authorities issued a maritime alert, advising boats not to put to sea.

The depression was packing maximum gusts of 50 kilometres an hour at its centre and was moving west at 20 kilometres an hour.

The weather bureau said the depression was now expected to cross the coast near Chumphon's Lamae district - not Nakhon Si Thammarat, as earlier predicted.

Chumphon weather chief Theerawat Theerarattapol forecast heavy rain till tomorrow with possible floods and landslides for Prachuap Khiri Khan, Chum-phon, Surat Thani, and Ranong. Strong winds and 2-4 metre swells were likely in the Gulf.

Koh Samui district chief Decha Kungsanan recommended small craft not put to sea, but ferries to the island were not interrupted.

Koh Pha-ngan district asked the Full Moon Party be postponed for public safety and for boat services to be suspended. Many tourists were reportedly stranded on Pha-ngan, and Koh Tao when the boat services were cancelled.

Region-11 disaster mitigation official Somchai Ramasut said Surat Thani was on 24-hour standby and rescue services were prepared for possible floods and landslides.