The Bank of Korea(BOK) now forecasts that South Korea's population will age at a faster speed than Japan sooner than expected.

The BOK said on Monday that the proportion of South Korea's elderly population, which ranks 29th among 37 Organization of Economic Cooperation and Development(OECD) states, will exceed that of top-ranked Japan before the previously-projected date of 2045.

In 2019, Statistics Korea estimated senior citizens in South Korea to account for 36-point-four percent of the population in 2043, surpassing that of Japan's 36-point-35 percent.

The BOK report cited the country's rapidly-declining birth rate and the COVID-19 impact on marriages and births as reasons behind the latest projection.

The population is also expected to begin to decline in 2022, which is sooner than the previously-forecast 2029.

The BOK report projected the COVID-19 shock to exacerbate the low marriage and birth rates, negatively impacting population changes for a significant period of time.