On Tuesday, New York-based China Labor Watch released into eight Samsung factories in China. It cites what it called a "long list of illegal and inhuman violations" including forced overtime, underage workers, and verbal and physical abuse.

Samsung could not immediately comment on that report, but on Monday, in response to an earlier investigation, it said it had a "zero tolerance policy" on child labor violations and that it was auditing its factories to ensure they comply with its policies and with local laws.

Samsung workers interviewed by IDG said their main complaint was how monotonous and dull their work is.

"The work we do now has nothing to do with what we learned in school," said a 21-year-old worker, surnamed Meng, who studied computer graphics and design at a trade school. She now spends eight hours a day producing motherboards for mobile phones, and sometimes works a further 12 hours on weekends, depending on Samsung's needs.

Meng came to work at the Samsung factory two years ago with 70 classmates from her school in Shandong province. Many of those classmates are no longer there. "They left because it wasn't really a good fit, or they were here too long and they wanted to learn something else. Some didn't like it," she said.