UPDATE 1-S.Korea plan to ease oil-blending rules to take effect from Thurs

* Traders to have more leeway in blending oil products in S.Korea

* S.Korea pushing to boost its role in international oil trading (Adds detail)

SEOUL, Oct 18 (Reuters) - South Korea said on Wednesday that its plan to ease blending restrictions at oil storage terminals would come into effect on Thursday, as the government continues its push to boost international oil trading in the country.

The world's fifth-largest oil importer in April approved legislation to loosen restrictions on companies blending refined fuels at oil terminals, but the exact start date was not released at that point.

Previously, international oil traders with storage tanks in South Korea were only allowed to mix oil products in bonded areas like tank terminals to export, according to an energy ministry statement and a ministry official.

But the new regulations allow them to trade their blended products locally through oil importers.

The energy ministry said in the statement that the move would help expand the country's oil trading business and transform its Yeosu and Ulsan ports into a Northeast Asian trading hub.

South Korea currently has 24 million barrels of storage capacity at its tank terminals in Ulsan and another 8.2 million barrels in Yeosu, Korea National Oil Corp says on its website.

(Reporting by Jane Chung; Editing by Joseph Radford)