Almost all infections so far have taken place in hospitals and the World Health Organization said it had found no evidence suggesting transmission of the virus outside hospital.
Sixteen patients were in critical condition as of Wednesday, the ministry said, while 67 people have recovered and been released from hospital.
South Korea's MERS outbreak began on May 20 when a 68-year-old man was diagnosed after returning from a trip to Saudi Arabia.
The virus since then has spread at an unusually rapid pace, sparking alarm in the Asia's fourth-largest economy and elsewhere in the region.
The outbreak dealt a severe blow to businesses from tourism to retail as people have shunned crowded venues and more than 120,000 foreigners cancelled planned trips to Seoul.
South Korea's central bank cut its key interest rate this month in a bid to counter the economic impact of the outbreak, but its chief on Wednesday said it was already starting to fade.
"The extent of the fall has declined from the first and second week of the outbreak, which is why we are hoping the impact is weakening," he said in comments carried by the Yonhap news agency.
There is no known vaccine for MERS, which has infected more than 1,330 people -- mostly in Saudi Arabia --