Bangkok  - Thai shares dropped 5.3 per cent in value Thursday on rumours about Thai King Bhumibol Adulyadej's health, brokers said.

The Stock Exchange of Thailand (SET) index ended at 692.72, down 38.75 points or 5.3 per cent, after a day of heavy trading amounting to 53 billion baht (1.5 billion dollars).

"This is the second day the market has been hit by rumours (about the king's health)," said Chaiyudh Jiwangkul, an analyst at Country Group Securities.

"This panic started abroad, not at home, but when locals saw foreign investors selling they have followed suit," he added.

King Bhumibol, 81, has been in hospital since September 19, suffering from a lung infection.

According to a statement issued by the Royal Household Wednesday evening, the inflammation in the king's lung had subsided but it will take more time for him to recover "as is generally the case with the elderly."

Most of the rumours about the king's health appear to have originated abroad.

"These are all rumours as far as I can tell," said Thitinan Pongsudhirak, a political scientist at Chulalongkorn University. "But now pressure is going to mount on the doctors and Royal Household to show evidence to the contrary."

King Bhumibol has reigned as Thailand's monarch for the past 63 years, providing stability to the country's often rocky political scene. (dpa)