Stock exchange and security officials have been ordered to find the people who generated rumours about His Majesty the King's health that caused share prices to plummet.
The instructions were issued on Thursday by Deputy Prime Minister Somkid Jatusripitak, who manages economic affairs, and Deputy Prime Minister Prawit Wongsuwon, who oversees security.
Mr Somkid said the rumours caused a steep fall in the SET index on Wednesday. He advised investors not to listen to rumour, saying they should have confidence in the potential of Thailand.
"I will tell the Office of the Securities and Exchange Commission to find out who released the negative rumours that affected share prices. Foreigners are waiting to buy, but Thai people are releasing rumours to hammer shares," he said.
"The nation is at a very crucial moment. Many things are starting to improve. Do not destroy them. There is no point."
Mr Somkid said he believed all Thai people were worried about the health of the King, but they should not believe rumours.
Gen Prawit, also the defence minister, said he ordered security authorities, police and the Technology Crime Suppression Division to tackle any websites and social media pages that distorted information and released rumours about the health of His Majesty.
He advised people in general not to be shaken by rumours. The Ministry of Digital Economy and Society was examining the overseas sources of the rumours.
The SET index had plunged 8.5% from its close last Friday to 1,376.35 points at the noon break on Thursday.