The gender pay gap in South Korea among companies required to disclose such information -- those with total assets of more than 5 trillion won ($5 billion) in affiliated companies -- narrowed slightly to 26.3 percent last year, a report showed Friday.

According to the Ministry of Gender Equality and Family's gender pay gap research, the average pay of all 2,647 companies subject to disclosure, including listed companies and companies subject to external audit, was 98.57 million won for men and 72.59 million won for women last year, resulting in a gender pay gap of 26.3 percent. This figure is a decrease of 4.4 percentage points from the previous year, when the gap was 30.7 percent for 2022.

It is estimated that the average pay for men and women in the disclosed companies increased year-on-year. In particular, women's pay increased by 20.6 percent, which is larger than men's pay increase of 13.6 percent, narrowing the gap a little, the report explained.

The increase in women's quantitative representation and longevity working at these companies is also likely to have had an impact, it added.

Women's employment across the companies inched up by 1.1 percentage points, from 26.6 percent in 2022 to 27.7 percent in 2023, and women's average number of years working in these companies increased by 0.2 years, from 8.9 in 2022 to 9.1 last year.

For comparison, the average number of years men worked in these companies was 11.9 years in 2023.

As a result, the gender gap in the average number of years worked for the disclosed companies fell slightly to 23 percent from 25.1 percent the previous year.

There were no fields in which women were paid equally to men, according to the report.

By industry, the smallest gender pay gaps were in the arts, sports and leisure-related services, with a gap of 16.5 percent; educational services at 18.5 percent; and the electricity, gas, steam and air conditioning supply fields at 19.5 percent.

In contrast, the industries with the largest gender pay gaps were: business facilities management or business support, and the rental business where women were paid 40.6 percent less than men; construction at a 43.5 percent difference; and wholesale and retail trade where female employees were paid a full 43.7 percent less than male employees.

South Korea has had the worst gender wage gap among the 38 member countries of the Organization for Economic Cooperation and Development for 27 years straight, according to 2022 data released in May. Luxembourg ranked first with a gender wage gap of 0.4.