Korea is expected to face an increasing annual tax burden of some 2 million won per capita by 2040 and about 5 million by 2060 as the country is set to increase its monthly basic pension for those over 65.

The National Assembly passed a bill allowing the poorest 70 percent of senior citizens to receive a monthly pension of up to 200,000 won beginning in July. It replaces a benefit that paid out up to 96,000 won a month.

This is raising concerns, as Korea is suffering a shortfall in tax revenue and a shrinking economically active population amid a rapidly aging society.

The number of people of working age ― those from 15-64 years old ― is expected to fall from about 37 million in 2015 to 22 million in 2060.