At least one person has died in Thailand's first tropical storm in three decades as it arrived on the south coast, knocking down trees and blowing off roofs in its path.

However officials have said the storm is losing speed, but they warned against the risk of flash floods.

Accompanying winds churned up high waves and gusts in the Gulf of Thailand as tropical storm Pabuk made landfall in the Pak Phanang district of Nakhon Si Thammarat province, where trees crashed down on houses to cause widespread damage.

Disaster mitigation officials said the person killed was among the crew of a fishing boat that capsized in strong winds near the coast of nearby Pattani province.

Another of the crew was missing, but four others were safe.

Weather officials warned of torrential downpours and strong winds in 15 provinces in the Thai south, home to one of the world's largest natural rubber plantations and several islands thronged by tourists.

Holidaymakers have been advised to avoid provinces on the Thai-Malaysia border.

Islands in the Gulf of Thailand such as Koh Phangnan, Koh Samui and Koh Tao are extremely popular with western tourists.

The National Disaster Warning Centre has sounded alarms around tourist beach destinations, including Koh Samui and Koh Phangan, urging people to leave high-risk areas for higher ground.

The storm "is expected to downgrade to be a tropical depression," the Thai Meteorological Department said in a statement.

"People should beware of the severe conditions that cause forest runoffs and flash floods."

The conditions are expected to persist into tomorrow. With airports and ferry services shut, people were advised to stay indoors until the storm passed.

During the past few days, 6,176 people have been evacuated to shelters from Nakhon Si Thammarat as well as the provinces of Pattani, Songkhla and Yala, the Department of Disaster Prevention and Mitigation has said.

The Nakhon Si Thammarat airport said it had closed, and low-cost Nok Airlines Pcl said it had cancelled all eight flights to and from the province.

The Surat Thani airport will also close from this afternoon to tomorrow, cancelling flights by Nok Airlines, Lion Air, and Thai Smile, a subsidiary of national carrier Thai Airways.

Earlier, Bangkok Airways Pcl said it had cancelled all flights to and from Koh Samui, where ferry services have also been suspended.