South Korea's energy imports jumped 14.6 percent in the first half of this year due to a hike in import prices for crude oil and natural gas, customs data showed Thursday.

Imports of energy, including crude oil, natural gas and coal, totaled 81.5 billion U.S. dollars during the January-June period, up 14.6 percent from the same period of last year, according to the Korea Customs Service (KCS).

The expansion was mainly attributed to a jump in import prices for crude oil and natural gas, which surged 11.3 percent and 26.2 percent on-year in the first half. Coal import prices also gained 3.7 percent over the cited period.

Despite the spike in value of energy imports, the import volume stood merely at 147.5 million tons during the first half, up 0.4 percent from the same period of 2011.

In terms of volume, oil imports grew 1.8 percent for the first six months of this year from a year earlier to 63.6 million tons, but coal imports contracted 0.9 percent to 62.1 million tons over the same period. Natural gas imports were almost unchanged at 21.8 million tons.

The customs office said that reduction and slower growth of energy imports in volume stemmed mainly from slowdown in global economic growth caused by Europe's debt crisis.