The Centre for Covid-19 Situation Administration (CCSA) on Monday warned there was still a risk of new Covid-19 infections.

The warning came despite the fact that Thailand on Monday recorded its 42nd consecutive day in which there have been no new local transmissions.

More than 3,000 illegal migrant workers had been detained while attempting to sneak into Thailand over the past month, said CCSA spokesman Taweesilp Visanuyothin, citing a report supplied by security authorities.

Many of them had been caught and detained by the Immigration Bureau, including some who had made their way into the inner provinces, while some had been sent back to their own countries, he added.

"So, while travelling during this long holiday, it is very important for everyone to never down let his or her guard [against Covid-19] as more of those who illegally entered the country may be around you," said Dr Taweesilp.

He also responded to findings from a new survey conducted by Suan Dusit Poll, which showed that two-thirds of people were feeling relaxed about the Covid-19 situation.

He said that was worrying and everyone was still being urged to wear face masks, wash their hands frequently and maintain social distancing until an effective vaccine was found.

As for the government's programme to allow in foreign patients seeking treatment for non-Covid-19 conditions, he said a total of 1,169 such people from 34 countries and 1,521 accompanying friends and family had registered to visit Thailand for such a reason over the next three months.

All of those people would be required to prove that they had tested negative for Covid-19 within 72 hours of leaving their countries, plus undergo a mandatory Covid-19 screening test at the airport upon arriving in Thailand to confirm they were still free of the virus and stay in hospital for at least 14 days before leaving, he said.