A local case in Krabi was among 12 new Covid-19 patients reported yesterday, raising Thailand's total infections to 3,830.
The local case was an Indian man, 37, who works at a restaurant in the southern resort province.
He tested positive on Wednesday while taking a health test for a work permit. He is being treated at a public hospital and his case is being investigated, the Centre for Covid-19 Situation Administration (CCSA) said, without revealing further details.
However, Supoj Pookaoluan, director of Krabi Hospital, said the man arrived in Thailand three months ago and had since been unable to return home.
He took a job at the restaurant while staying with three friends and relatives at a house in Muang district.
He later applied for a work permit and had a health checkup on Wednesday at a private hospital in the district. The result was positive with no symptoms.
He was later sent to Krabi Hospital, which tested him and three other people living in the house.
Their results were negative so the hospital allowed the three people staying with him to go home, while the infected man remained in a negative-pressure room at the hospital for more tests.
The third test on Friday night was negative and the hospital sent his blood samples to a medical science centre in Phuket for a retest. The result was not known as of press time last night.
According to the Krabi provincial health office, 19 people were in contact with him -- 11 at the private hospital and eight at his house on Koh Phi Phi. They have all tested negative.
Also yesterday, the Public Relations Department's Covid-19 information centre said on social media that the Public Health Ministry had approved a proposal to shorten the quarantine period to 10 days for low-risk countries.
They include China, Vietnam, Taiwan, South Korea, Australia and New Zealand.
The 14-day quarantine period will remain in place for arrivals from all other countries.
The proposal will be sent to the CCSA, which will have the final say on the issue.
In addition to the Krabi case, nine other cases reported yesterday were quarantined arrivals from seven countries.
There were two each from France and the United States and one each from the United Arab Emirates, India, Mexico, Switzerland and the Netherlands.
The remaining two new cases were both Myanmar nationals, who have already been sent home.