BANGKOK - Two immigration officers at Bangkok's main airport have the coronavirus and may have handled the passports of visitors to Thailand, a health official said on Wednesday (March 11).

The men, both working at Suvarnabhumi airport, fell ill on March 7 and 8 respectively and potentially came into contact with arriving passengers in the days before their diagnosis.

One of the officers was among a team leading health screenings of Thai returnees from South Korea - which has reported the second-most Covid-19 infections in Asia after China.

"They were not working at the same spots," Mr Sopon Iamsirithaworn of the Disease Control Department said.

"There is a chance they came into contact with foreigners or touched passports," he added.

Thailand's Interior Minister said on Wednesday it will suspend visa-free arrivals from South Korea, Hong Kong and Italy, as well as visa-on-arrival from 18 countries - including China and India.

All affected visitors must apply for visas at Thai embassies in their own countries and present a medical certificate.

Thailand's economy is heavily reliant on tourism.

The deadly virus has hammered the sector, costing the country billions of dollars, mainly after Chinese tourists were quarantined on the mainland or stayed at home.

Many western visitors have also cancelled holidays or deferred bookings as Thai authorities issue a baffling barrage of advice.

After days drip-feeding conflicting information to holidaymakers, health authorities said last Friday there will be no compulsory quarantine for people from countries hardest hit by the virus.

Thailand has reported 59 cases of the new coronavirus, but there are concerns that the low figure may be a reflection of a very limited testing programme.

Flag carrier Thai Airways said from Friday it will suspend all flights to Italy, where over 630 people have died, with around 10,000 infected so far.

For the latest updates on the coronavirus virus, visit here.