Their wage level was 10 times that of ordinary employees who received 61.9 million won on average.

Nearly half of the companies paid around 100-500 million won to registered board members, while 16.6 percent gave over 1 billion won, they noted.

About a quarter of the companies paid around 60 million won on average to their rank-and-file workers, while 19.5 percent and 18.3 percent paid over 50 million won and 40 million won.

Half of the employees at financial companies received roughly 80 million won, the highest level among all sectors, with three out of 10 earning over 100 million won, data showed.

While the institute released the report based on regulatory filings released by listed companies, market watchers point out that the data fall short of depicting the exact market situation due to a lack of standardized standards for pay disclosure. 

Under a 2013 law designed to enhance corporate transparency, companies are required to release the salary information of executives who earn more than 500 million won a year if they are members of the board of directors.

In real practice, some companies included the wages of senior executives who do not belong to board of directors, while others only disclosed pay checks of ordinary employees and their managers.

Oh Il-sun, a director of the research institute, said the current rule should be revised to define the exact scope of those who are subject to disclosure to better inform the public.

"A standardized guideline is needed to reduce the misunderstanding of employees' salary," Oh said. "It could classify ordinary employees and unregistered senior executives separately when it comes to revealing their salaries." (Yonhap)