The number of people unemployed for six months, who are classified as long-term unemployed, reached a 13-year high in May this year, according to Statistics Korea on Thursday.

Some 120,000 were long-term unemployed, accounting for 11.96 percent of the jobless population. It marked the highest since 2004.

Companies in South Korea usually hire in August or September, when the respective number slightly declines. Employment by such firms, however, has been lackluster due to weak business performances and internal and external economic uncertainties.