A community of about 300 Moken people on Koh Surin was isolated after 22 of them tested positive for COVID-19.
Health officials of Khura Buri district conducted antigen tests in the community on Nov 21 and found positive results with the 22 islanders.
The people were transported to a community isolation center in Khura Buri pending their RT-PCR tests. Health officials also isolated the Moken community on Koh Surin and had other people in the community do home isolation to contain the disease.
Initial investigation found that an earlier infected Moken person from Koh Phayam in Ranong province had visited the community for burial.
Meanwhile, Phuket recorded 83 new COVID-19 cases on Sunday and they included a visitor in the Phuket Sandbox program.
New daily caseloads in Phuket were rising from 48 on Nov 15 when local disease controls were eased to permit alcohol consumption at eateries, school reopening, the influx of Thai and migrant workers and crowd gatherings.
The 83 new cases formed the biggest number over the past 20 days but there has not been a big cluster of COVID-19 cases in Phuket.
Thailand on Monday reported 6,428 new coronavirus cases and 49 more fatalities over the past 24 hours. (TNA)