The latest fatality was a 68-year-old woman who contracted the virus at a hospital in Pyeongtaek City, 65 kilometres south of Seoul, the Health Ministry said.
It said all the 14 deceased had pre-existing health conditions, with the most recent fatality suffering from hypertension and hypothyroidism.
Twelve new infected patients brought to 138 the total number of confirmed cases, in the largest outbreak of the virus outside Saudi Arabia.
The new cases included an ambulance driver who fell ill after transporting a 75-year-old infected woman to Samsung Medical Centre in southern Seoul on June 7, where she died three days later.
Out of 133 people whose contacts have been traced, the largest single group of 60 people have contracted the disease at Samsung Medical Centre, one of the largest hospitals in Seoul.
Five other cases are being investigated to find out how and where the patients were infected.
The first infected patient in South Korea was diagnosed on May 20 after a trip to Saudi Arabia.
The 68-year-old man visited four medical facilities, infecting other patients and medics, before he was finally diagnosed.
Meanwhile, three of Thailand’s international airports have tightened precautionary measures to prevent the spread of Mer.
The three airports are Suvarnabhumi, Hat Yai and Chiang Mai. Sirot Duangrat, director of Suvarnabhumi airport, yesterday (June 12) said three thermal imaging cameras have been in operation at two immigration stations in the arrivals hall at the airport since June 2 in order to screen the body temperatures of incoming passengers who could have been exposed to the virus.
Airport medical teams are also on standby and monitoring passengers from countries affected by Mers.
Facial masks, hand wash and health advisory cards are being provided for both airport authorities and passengers.
Pamphlets containing preventive measures are also being distributed to tourists at check-in counters, baggage carousels and departure lounges.
Additional reporting Bangkok Post