Prosecutors in Brazil are suing Samsung over allegations of labour abuses at a Zona Franca de Manaus factory.
The Korean company is being investigated for allegedly having staff work long shifts for dozens of days in a row, according to the Korea Times.
The Zona Franca de Manaus factory employs 6,000 workers who build budget smartphones, mid-market TVs and other electronics for Samsung.
The Zona Franca de Manaus is a special economic area where a lot of factories, particularly electronics factories, operate. Once established in the free zone, companies are exempt from import and export tax, as well as making them liable to discounts from government and exemption from property tax for ten years.
Samsung has told Brazilian authorities that it will cooperate.
In a statement, the company said: "We will make our best efforts to address the allegations by Brazil's Ministry of Labor and Employment. We have so far been consistent in providing competitive welfare systems and creating safe working environments.
"As Samsung is a global company, we strictly abide by all laws in the regions we operate".
Last year, a China Labor Watch report accused Samsung of complicity in worker abuses at its factories, including underaged workers, forced overtime, gender discrimination, and verbal and physical abuse.