A suspected Cambodian trafficker and 20 illegal migrants were arrested in a raid opposite the Rong Kluea border market in Sa Kaeo province's Wednesday.
Police and soldiers stormed a rented room at the Det Thai market room in Aranyaprathet district finding six men, 11 women and three children. None had travel documents, Daily News Online reported.
The accused human smuggler, Nao Sianghai, 42, was taken into custody.
All the migrant workers told police through an interpreter that they had sneaked into the country on foot. They were led by members of a Cambodian trafficking gang.
After arriving on Thai soil, they were taken to Mr Nao's apartment where they waited to be sent to jobs in Bangkok. They said they had to pay 2,500 baht each to get smuggled in.
Mr Nao claimed he had been hired by a Cambodian job broker to ride a motor-tricycle to take the migrant to his room. He charged them 300 baht each for the services.
He denied any involvement in human trafficking, but police were not convinced as his name was on a police blacklist of wanted human smugglers.
Officers planned to extend their investigation to arrest other gang members.