Yangon, May 19 (IANS): Nearly 150 Myanmar migrant workers locked up inside a shrimp factory near Bangkok have been rescued by Thai police.

Kyaw Thaung, a spokesperson for the Burmese Association in Thailand (BAT), told The Irrawaddy newspaper that they came to know about their plight from another worker.

The 146 workers were forced to work like slaves in the factory basement. A co-worker secretly filmed their plight and it was used as evidence against the employer, BAT said.

"I had to shoot videos secretly, and I was afraid of being found out by the factory thugs. I don't have any documents to stay in Thailand," the co-worker said.

His evidence was submitted to the Thai Police and a UN agency, and after which the owner was arrested, the Mizzima News reported Thursday.

The workers had to work for 20 hours a day without any break and some of them who were unwell were not allowed to receive treatment.

According to BAT, currently four million Myanmar migrant workers are in Thailand and only half of them have travel documents.