South Korea's Finance Minister Bahk Jae-wan warned on Tuesday over the possible depletion of the national pension fund as the Asia's No.4 economy is the fastest aging country across the globe.

"Population aging in Korea is progressing faster than any other country. The fastest aging boosted fears over the faster- than-expected depletion of the national pension fund," Minister Bahk said at a seminar held in central Seoul.

South Korea is the world's fastest aging country. The country was predicted to become a super-aged society in 2026 after making an aged society in 2018, according to the United Nations (UN). It already became an aging society in 2000.

South Korea's national pension fund, introduced in 1988, is a pre-funded system that has a structure of paying less and receiving more. The structure has been maintained to achieve the goal of income redistribution for the low income class who receive benefits three to four times their pension contributions.

The National Pension Service (NPS), the fund operator, expected the fund to be depleted in 2060, forecasting that the fund's deficit would amount to 99 trillion won (90.87 billion U.S. dollars) in 2050 and 365 trillion won 2060, 534 trillion won in 2070 and up to 657 trillion won in 2078.

Minister Bahk cautioned over the worsening management conditions for the national pension fund. The minister pointed out the deepening uncertainties in the global financial market caused by the eurozone's fiscal crisis, the U.S. fiscal cliff issue and the China's economic slowdown.

He noted that it became hard for the pension fund to earn an appropriate level of return amid the trend of low growth and low interest rate, adding that the pension fund needs to find how to improve the level of return for sustainability and stability.