The nation's total fertility rate, the average number of babies born to a woman over her lifetime, stood at 1.187, down 0.110 points from a year earlier, the lowest among the 34 member states of the Organization for Economic Cooperation and Development (OECD), the report said.
The OECD member states' fertility rate averaged 1.7 in 2011.
The number of babies born in 2013 totaled 436,500, down 48,100 or 9.9 percent from 484,600 tallied in the previous year, according to the office, Statistics Korea.
The report attributed the downward trend in part to what it called a “base effect” caused by the so-called “birth fever” which hit the country in 2012, the "Year of the Black Dragon“ according to the Lunar Calendar. In the Orient including South Korea, the dragon represents a symbol of divinity.