Hundreds of factory workers at a Chinese supplier to Fast Retailing Co. are striking over the dismissal of some of the employees, forcing production to shut down, a labor rights group said.

All of the about 900 workers at Artigas Clothing & Leatherwear Co. in the southern Chinese city of Shenzhen joined the strike after a number of them started it on June 8, Alexandra Chan, project officer of Hong Kong-based Students and Scholars Against Corporate Misbehavior (SACOM), said in a telephone interview.

The supplier has been transferring equipment out of the factory and fired older workers as it plans to relocate the facility, Chan said, citing the workers. About 500 employees have been camping overnight at the plant to prevent more production machines being moved out, she said.

Fast Retailing confirmed there's a strike at Artigas, which belongs to its manufacturing partner Lever Shirt Co., it said. The maker of Uniqlo casual wear has requested the management of Lever Shirt to reach a peaceful resolution with the workers, it said in an emailed statement.

Earlier this year, nongovernmental organization SACOM released a report that highlighted labor abuses at two other Fast Retailing-related factories in China, Dongguan Tomwell Garment Co. and Pacific Textiles Ltd., prompting an investigation by Fast Retailing.

The Yamaguchi-based company, controlled by Japan's richest man, Tadashi Yanai, pledged to improve working conditions and said it will work with outside groups to monitor work conditions at those factories.