During the reported year, the number of workers permitted to join unions arrived at 19.56 million, up 2 percent from the previous year. Senior public officers are not included in this figure, as they are not permitted to join unions.

The unionization rate peaked at 19.8 percent in 1989, two years after a wave of labor strikes swept across South Korea, before falling to 9.8 percent in 2010.

Since 2010, the rate hovered in the low single digits and rose to the high single digits last year, the highest level since the 10.8 percent recorded in 2008.

The Federation of Korean Trade Unions, South Korea's largest umbrella body for labor unions, had 872,000 members, while membership of the Korean Confederation of Trade Unions  was 711,000. Members of the two labor umbrella organizations accounted for 75.8 percent of all unionized workers.

Given the FKTU and KCTU expanded their organization in a competitive way this year, the memberships of the two groups are expected to increase, with the number of unionized workers affiliated with KCTU projected to top the 800,000 threshold.

But experts say the unionization rate remaining in the 10 percent range could illustrate the hardship faced by labor unions.

The government has been pushing for the joining and ratification of key conventions of the International Labor Organization on protecting laborers' rights.

The ministry's data also laid bare the concentration of labor unions in large companies. While the unionization rate rose to 57.3 percent in large companies employing more than 300 people, companies with fewer than 300 employees and more than 100 saw the rate fall to 14.9 percent. The rate for companies employing 33 to 99 workers came to a mere 3.5 percent.

This means that workers at mid-sized and small companies do not receive the protection of labor unions. (Yonhap)