A British human rights activist who investigated alleged abuses at a Thai fruit processing factory went on trial in the first in a series of criminal lawsuits filed against him by the company.
Natural Fruit is accusing activist Andy Hall of defamation in the wake of a report he helped write last year for the Finland-based watchdog group Finnwatch that detailed poor labour conditions in seafood and pineapple export companies in Thailand.
The report investigated a factory owned by Natural Fruit that employs hundreds of migrants from neighbouring Burma.
It found the company illegally confiscated passports, paid below minimum wage and overworked staff in sweltering conditions so hot that heat strokes were common. Natural Fruit disputes the accusations.
Phil Robertson, deputy director of Human Rights Watch's Asia division, criticised the trial.
He said Natural Fruit "has decided to take a punitive approach rather than address the problems in their factory.
"This is all about trying to intimidate people who are prepared to investigate human rights abuses .... and if (Hall) is convicted, it could have a chilling effect on independent research on human rights in Thailand."
Mr Hall, 34, faces up to seven years in prison.
There are four criminal and civil cases pending against Mr Hall, whose passport was confiscated by Thai authorities as a condition of bail set in June.
The first relates to defamation charges for an interview on the subject he gave to Qatar-based Al-Jazeera television.
The trial comes after the US earlier this year demoted Thailand to the lowest level in its annual rankings of governments' anti-human trafficking efforts, principally over its failures to do enough to stop abusive practices in the Thai seafood industry.
The so-called "tier 3" rankings for Thailand means the country could face US sanctions.
Mr Hall has worked in Thailand for years and is an outspoken activist on migrant issues.
Millions of impoverished migrants, largely from Burma and Cambodia, have left their countries to work in Thailand.
Some do not have legal papers, and many work low-skilled jobs for long hours at pay below their Thai counterparts. They typically lack health and social security benefits.
Thailand's elected government was overthrown in a bloodless May 22 military coup, whose leaders have silenced their once-thriving political opponents, threatening them with prosecution if they disturb the public order.