China's Commerce Ministry on Monday imposed five-year duties on solar-grade polysilicon imports from the United States and the Republic of Korea (ROK).

Starting on Monday, China will apply anti-subsidy duties of up to 2.1 percent and anti-dumping duties ranging from 53.3 percent to 57 percent on polysilicon imports from the United States. The rates for imports from ROK are set between 2.4 percent to 48.7 percent.

The duties will last for five years, the ministry said.

The decision came after China began to levy provisional duties on polysilicon imports from the two countries last year following preliminary investigations that found exporters dumped their products on the Chinese market.

Solar-grade polysilicon is an important material for making solar cells, a sector fraught with trade disputes.

In 2012, the US government imposed anti-dumping and countervailing duties on crystalline silicon photovoltaic cells from China.

The US commerce department said Chinese producers and exporters sold solar cells in the US market at dumping margins ranging from 18.32 percent to 249.96 percent, and they received countervailable subsidies of 14.78 percent to 15.97 percent.

Timeline of China-US solar disputes