Out of the 23, 17 were from the same Seoul hospital emergency room where the country's first patient was hospitalised from May 15 until being confirmed MERS-positive on May 20, the ministry said. [What is Middle East Respiratory Syndrome coronavirus (MERS)?: Explained]
The remaining six new cases came from two hospitals in Daejeon city, Xinhua reported.
An 80-year-old man who had tested positive for MERS, also from Daejeon, died on
Monday, taking the number of deaths from the outbreak to six.
South Korea became the world's second-most MERS-contagious country after Saudi Arabia, where over 1,000 cases have been identified since the first case was reported in 2012.
The World Health Organization (WHO) is slated to send a team to South Korea this week to review and assess the situation.