The personal details of foreigners from what is believed to be the Nakhon Si Thammarat immigration office website have apparently been leaked, sparking concerns over their safety.
Deputy Prime Minister Prawit Wongsuwon, who oversees security affairs, has ordered the removal of the details from the website.
The details, which include their names, nationalities and professions, should be regarded as "confidential", Defence Ministry spokesman Kongcheep Tantrawanich quoted Gen Prawit as saying yesterday.
An alert about the leak was posted on the Facebook page of website-based journalist and lecturer Andrew MacGregor Marshall.
"You need to take urgent steps to protect yourself. Thai immigration data has been shared online," he wrote on his Facebook page.
Foreigners living in Phuket and Samui should also take extra care, he said.
His Facebook page also reported another leak of foreigners' personal data yesterday. It is the database of the Bureau of General Communicable Disease, Department of Disease Control (DDC) which shows names, Thai addresses and passport details of foreigner arrivals in Thailand.
However, Vichan Pawun, DDC spokesman, played down the issue.
"We need the information to protect every Thai citizen," Dr Vichan said. "It is our authority to acquire the information and the leaked data was old information since the Ebola situation.
"In fact, our IT staff already fixed the system. I'm unsure how the information managed to escape again," he said.