South Korea said Monday it plans to import 200 tons of urea from Vietnam next week in the latest move to help ease a supply shortage of urea water solution, a key material used in diesel vehicles to reduce emissions.

The amount is part of 10,000 tons of urea that South Korea hopes to import from Vietnam and other nations to make urea water solution, according to the finance ministry.

Separately, South Korea is set to import 27,000 liters of urea water solution from Australia, including 20,000 liters planned for this week.

The move came as President Moon Jae-in ordered aides to "make utmost diplomatic efforts to secure" urea water solution from foreign countries.

To help facilitate the imports, the government plans to cut import tariffs on the material to zero from the current 5-6.5 percent.

South Korea has been grappling with a shortage of urea water solution, known as diesel exhaust fluid, and its surging prices in recent weeks, as China tightened exports of fertilizers and related materials, including urea, in October amid a power crisis caused by a coal supply shortage. Coal is the main feedstock for urea.

South Korea heavily relies on China for its supply of urea water solution, as 97.6 percent of its imports came from China in the first nine months of this year.

The number of diesel vehicles is estimated at some 10 million, about 38 percent of registered cars in South Korea.

Of them, 4 million diesel cars, including 2 million freight trucks, must install equipment that requires the use of urea solution to cut emissions under the country's tightened emission rules adopted in 2015. (Yonhap)