The announcement comes as the central bank lowered its key interest rate to a historic low on Thursday. It was a response to a slump in exports and the prospect that MERS could slow the economy.
Bank of Korea policymakers cut the policy rate by a quarter of a percentage point to 1.5 percent, the second rate cut this year. In March, the bank lowered the key rate and downgraded its growth forecast for Asia's fourth-largest economy as exports continued to slump.
Analysts initially expected the central bank to leave the policy rate unchanged. That view changed this month as the MERS outbreak caused panic in South Korea.
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