By Sebastien Malo

NEW YORK (Thomson Reuters Foundation) - Rural Cambodian villagers have filed a lawsuit against four U.S. and Thai companies, accusing them of trafficking and making them work in forced-labor conditions in a Thai seafood factory.

Their civil complaint filed in California federal court accuses the four companies in a joint venture of violating the Trafficking Victims Protection Act, a U.S. law that aims to prevent human trafficking.

Retailing giant Walmart purchases shrimp and other seafood from the companies, two of which have U.S. offices, according to the complaint.

Thailand's reputation has suffered in recent years after numerous investigations by news organizations and rights groups into human trafficking, slavery and violence in its multi-billion dollar seafood industry.

It has vowed to crack down on human trafficking and slavery and recently introduced reforms to its fisheries law.

The five men and two women filing suit in a Los Angeles court claim that after they left their homeland for Thailand, factory managers confiscated their passports and made them work up to six days a week for wages that were less than promised.

Some "were reduced to eating seafood they found washed up on the beach," the complaint said.

They were not allowed to retrieve their passports to leave and return home, it said.

"What happened to me was wrong," said Keo Ratha in a statement accompanying the lawsuit. "I filed this suit so companies would think twice before exploiting trafficked workers in the future."

The complaint claims the Cambodian workers were victims of involuntary and debt servitude, forced labor and human trafficking in 2010 and 2011.

The named companies include Rubicon Resources, incorporated in Delaware with an office in Culver City, California, and Wales & Co. Universe Ltd., incorporated in Thailand but registered to conduct business in California, the complaint said.

The two Thai companies are Phatthana Seafood and S.S. Frozen Food. No lawyers were listed in court documents for the defendants.

Walmart did not respond immediately to a request for comment, Rubicon Resources did not answer an email and telephone calls and Wales & Co. Universe could not be reached.

The workers are seeking an unspecified amount of money for unpaid wages, mental anguish, pain and suffering in the suit, filed on Wednesday in U.S. District Court for the Central District of California.

"These are lovely, hard-working and decent people who really deserve better," their lead attorney Agnieszka Fryszman told the Thomson Reuters Foundation.

Nearly 21 million people globally are victims of forced labor, an industry that generates $150 billion a year in illegal profits, according to the United Nation's International Labour Organization (ILO).

(Reporting by Sebastien Malo, Editing by Ellen Wulfhorst. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, property rights and climate change. Visit http://news.trust.org)