People were told to refrain from outdoor activities and those in need could get face marks at local public health offices and hospitals, said Dr Samruam Danprachankul.

Satun Governor Manit Wattanasen said he had officials closely watching the haze, and if it lingered in Satun skies for over three days he would have a weather-inspecting mobile unit from Songkhla check the air quality.

Health official Boonleu Nuanchan in Yala's Betong district warned the smoke would cause eye irritation, coughing, stuffy noses and breathing difficulties, and aggravate the conditions of patients with allergies, lung disease and asthma. He urged those experiencing eye irritation, eye redness, sore throat, queasiness and vomiting to consult a doctor immediately.

Late yesterday the haze reached Songkhla, causing poor visibility for  transport, especially fishing boats in the Gulf of Thailand, which could now see only as far as 100 metres.

Meanwhile, the Southern East Coast Meteorological Office said the haze would cover the lower South for several days at least due to the influence of the southwestern monsoon and the lack of rainfall on Indonesia's Sumatra Island.