Health officials are monitoring about 20,000 Chinese tourists currently in the country, as they start to return home after the Lunar New Year.
Dr Sopon Iamsirithavorn, director of the Bureau of General Communicable Diseases, said on Monday that about 20,000 Chinese visitors were here and were about to depart.
"Most of them have not shown any fever symptoms, and about 80% of them are from Wuhan," he said after a meeting at the Public Health Ministry in Nonthaburi province.
Dr Tanarak Plipat, deputy director-general of the Disease Control Department, said tour companies were sending their visitors back to China, either to their hometowns or nearby destinations if their native areas were sealed off.
The Public Health Ministry said about 5,000 extra health officials had been assigned to cope with the novel coronavirus outbreak.
Officials did not explain how the 20,000 tourists in the country were being monitored.
Officials were screening visitors arriving at Bangkok, Don Mueang, Chiang Mai, Phuket and Krabi airports around the clock. The strict screening had been expanded to cover arrivals from Changchun and Guangzhou, newly declared as outbreak zones, in addition to Wuhan, where the new virus was first detected.
From last Friday to Sunday 3,186 people arrived on 24 flights from Guangzhou, and 363 from Changchun. They were all screened for signs of illness.
Eight people had been found infected with the novel coronavirus in Thailand and 48 others, mostly Chinese, placed under observation, according to the health ministry.