South Korea saw a greater reliance on China for rare earth supplies in 2011, with China accounting for nearly 80 percent of South Korea's rare earth imports, customs data showed Monday.

South Korea purchased a total of 282 tons of rare earths from China last year, accounting for 78 percent of the country's total imports of 360 tons, according to the Korea Customs Service.

South Korea's dependence on China for rare earths in 2011 rose by 13 percentage points from a year earlier, the data showed.

Rare earth materials are key components of many modern-day technologies, including hybrid electric vehicles, liquid crystal displays and other high-tech equipment.

Although South Korea is a leading exporter of semiconductors and smartphones, it depends almost wholly on outside supplies for the rare earth materials used in making these high-tech items.

"We are now importing rare earth materials from 18 countries, up 3 countries from before but our dependence on China has been increasing," the agency said.

"High reliance on a single country leaves us vulnerable to possible price hikes caused by market monopoly," it said while stressing the need for finding alternative materials and diversifying import sources.