Authorities have tightened border controls to prevent illegal entry and the spread of Covid-19 from neighbouring countries.
Deputy government spokeswoman Rachada Dhnadirek said on Friday that Prime Minister Prayut Chan-o-cha instructed security authorities to step up surveillance along the border to stop migrants sneaking into Thailand through natural border crossings.
The prime minister also stressed that local quarantine facilities and field hospitals must be laid on to accommodate Thai returnees crossing the border from neighbouring countries, Ms Rachada said.
Border patrol police have set up an additional 14 field hospitals for illegal foreign migrants who have been infected with Covid-19 to prevent the disease from spreading to local communities, she said.
Gen Prayut also ordered authorities to arrest and take tough action against illegal labour smugglers and any state officials complicit in the crime, the spokeswoman said.
Foreign Ministry spokesman Tanee Sangrat said on Friday that the Centre for Resolution of Security Emergency Situation has been cracking down on illegal migrants and smugglers.
Between Jan 1-May 20, a total of 17,627 Thais and foreign migrants from neighbouring countries were arrested for illegal entry. Of them, 1,853 were Thais; 7,365 were from Myanmar and 5,464 were Cambodian. Others included 1,089 Lao nationals, and 33 Malaysians, Mr Tanee said. He said Thais who want to return home must register for certificates of entry (COE) from Thai embassies and consulates. Registrations can be made at http://dcaregistration.mfa.go.th.
He said immigration checkpoints are open on Mondays, Wednesdays, and Fridays for Thais who want to return via land border crossings from the four neighbouring countries of Myanmar, Cambodia, Laos and Malaysia.
For those who want to enter Thailand via waterway checkpoints or by ship, crew members who are Thai must register for COEs before entry, while foreign crew members are still not permitted into the country, except for humanitarian or economic reasons, Mr Tanee said.
They may include captains and crew of cruise liners or yachts visiting Thailand to help boost the country's economic recovery. They must obtain a visa and COE from the Foreign Affairs Ministry and undergo self-quarantine onboard their vessels at sea for 14 days.
For cargo ships entering Thai waters, they will be allowed to dock for a specified period and then must leave immediately, with no crew members allowed to disembark, he said.