Lee Joong-keun, head of the Korean Senior Citizens Association, speaks during his inauguration ceremony held at the Korea Chamber of Commerce and Industry in Seoul on Monday. (Yonhap)

The head of a senior citizens' association in South Korea proposed on Monday that the government raise the standard age classifying people as senior citizens from the current 65 to 75, arguing it is necessary to address the country's demographic imbalance.

"Currently, the senior citizen population is about 10 million, but the figure is expected to double to 20 million in 2050," Lee Joong-keun, the new chief of the Korean Senior Citizens Association said during his inauguration ceremony held at the Korea Chamber of Commerce and Industry in Seoul.

The official standard defining people 65 or above as senior citizens was set in 1981 as part of a preferential treatment scheme for the elderly under the Welfare of Senior Citizens Act. For example, those 65 or older are eligible for free subway rides.

"There are concerns that out of the remaining 30 million people, excluding the 10 million people under age 20, the 20 million who are in the working-age population will need to focus heavily on supporting the welfare of the 20 million senior citizens, which could strain workforce productivity," said Lee, 83, who is the founder of Booyoung Group, a local builder.

Lee argued that changing the standard age for being considered a senior citizen by raising it one year each year until it reaches his suggested target age of 75 would create a smaller number of only 12 million such "senior citizens" in 2050, adding that he plans to ask the government to implement this change.

He also said that along with raising the legal age for senior citizens, the legal retirement age at companies -- 60 -- should be increased and the national pension system -- where the official age to receive full benefits is currently 63 -- should also be changed with it.

"If the government raises the official retirement age, I would like those aged 65 to receive 40 percent of the highest salary they were earning before that age in the first year in which the age of senior citizens is raised. Then, when they're 75, I'd like them to receive only 20 percent of their peak salary. This way they'll remain in the workforce 10 years longer (and earn significantly and progressively less over the 10-year period)," he argued.

"The years between 65 and 75 should serve as a 10-year transitional period before becoming a 'senior citizen,'" according to him.