South Korea is planning a stimulus package to counter potential economic slowdown that would stem from weak exports and the negative impact of the Middle East Respiratory Syndrome (MERS) outbreak.

The finance ministry on Thursday announced a $13.5 billion stimulus, which include an unspecified supplementary budget, and downgraded its growth and inflation outlook.

The ministry lowered its growth forecast for 2015 to 3.1 percent from 3.8 percent and inflation projection to 0.7 percent from 2 percent. The economy is forecast to expand 3.5 percent next year.

Exports are forecast to shrink 1.5 percent this year and imports to fall 7 percent largely due to falling oil prices. The current account surplus is seen rising to $94 billion this year.

The outbreak of disease in Asia's fourth-largest economy has reduced consumer spending and tourist arrivals amid drought in many areas.

The government announcement came after the central bank cut its key rate to a record low 1.5 percent earlier this month to spur consumer spending and exports.

The MERS disease has affected 180 and killed 29 people since May 20. Consequently, more than 120,000 tourists canceled their visit to South Korea.

In June, consumer confidence fell to its lowest level since late 2012, data released by the Bank of Korea showed today. The index came in at 99 versus 105 in the previous month.

The ministry said with the recovery momentum yet to be firm enough due to sluggish exports, the outbreak of the MERS can lead the economy to undershoot its expected growth path.