The figure had stayed in the 10 percent range before exceeding the 20 percent level after the 2008 global financial crisis and hitting the mid- and upper-20 percent band after the 2012 European fiscal crisis.

After hovering around 25 percent recently, the ratio rose to 26.1 percent in September and 27.8 percent in October.

The jump in the ratio is widely seen as reflecting the tough market situation for those who have been out of the workforce for a long period of time, as well as young jobseekers.

"There is an upturn in the number of job quitters who remain unemployed for a long time amid no signs of improvements in the labor market," an agency official said.

South Korea's jobless rate stood at 3.2 percent in November, up 0.1 percentage point from a year ago. The unemployment rate for people aged 15-29 rose to 9.2 percent from 8.2 percent a year earlier. (Yonhap)