The protest at the sprawling Merton Co. plant in the city of Dongguan began in the company dormitory on Saturday, said China Labor Watch, a group run by Chinese exiles based in New York.
Police were sent in to calm the situation, but the protest did not end until the next day, said the group. It said hundreds of workers joined in the protest and dozens were detained, but gave no details of damage or injuries.
Merton's Web site said the Dongguan factory makes toys and gifts for multinationals, including McDonald's, Disney, Mattel, Warner and DC Comics.
Dongguan, just across the border from Hong Kong, lies at the center of China's export manufacturing industry, which relies heavily on low wages to remain competitive, the AP reports.
While the protest could not be immediately confirmed, the report underscores the Spartan conditions endured by Chinese factory workers, most from the impoverished countryside, the AP reports.
It said about half that amount is deducted for meals and lodging, while workers also face pay cuts if they refuse to work up to 70 hours of overtime each month, the group said.
Take-home pay for most workers averages about 700 yuan (US$88; Ђ 70) a month, it said, an amount about average for Chinese workers.
Spokespeople at Merton's corporate headquarters in Hong Kong did not immediately return requests for comment.