The suspect was identified as Vitoon Tongsin. He was apprehended with 20 male and female Lao.
Mr Vitoon confessed the labourers were charged with an import fee at Bt1,600/person before they were sent further to other agents in the capital.
Police had had traces of the human trafficking ring to have transported the foreign labourers from the northeastern province of Ubon Ratchathani to Bangkok. A checkpoint was thus set up to intercept vehicles of the suspects in Saraburi province.
The imported workers were to be dropped in Pathum Thani province near Bangkok before being picked up again and delivered to would-be employers in the capital, according to Anti-Human Trafficking Division (AHTD) police.
Initially, the suspect was charged with illegally bringing in and harbouring migrants to Thailand. Punishment is up to five years with a fine of up to Bt50,000.