Three of the workers were aged under 18 and the others were aged 19 to 21.

Thirty police and administrative officials raided the bar at about 10.30pm and arrested bar manager, Jit Namkan, 43.

Police seized evidence including hundreds of unused condoms, three used ones and hundreds of tin chips that the women were required to collect from customers as payment. The women could only exchanged the chips for cash when they visited home.

Police searched a nearby commercial building belonging to the bar’s owner, Phong Jarunai, where he kept the workers and found a pistol with ammunition in his pickup. The bar owner allegedly had some of the young women work at a watermelon garden or a noodle shop in the day and work in the bar at night.