In 2065, the final year covered by the latest estimates, the population is expected to slip further to 88.08 million, against 127.09 million in 2015, the institute said.

The share of the elderly, or people aged 65 or older, in the overall population is estimated to rise to 38.4 pct in 2065 from 26.6 pct in 2015.

The institute forecast that the nation's total fertility rate, or the average number of children one woman is expected to give birth to in her lifetime, at 1.44 for 2065, higher than 1.35 projected for 2060 in the previous 2012 estimates, reflecting recent rises in the number of women in their 30s or 40s who get married or have babies.

Due of the estimated rise in the birthrate, Japan's population would slip below the 100-million-threshold five years later than what was projected in the previous estimates.

The latest estimates, however, suggest that Japan is having difficulty halting the acute population decline and the rapid aging of society.

The population estimates, revised about every five years based on census results, are used as basic materials for the government in work on the design of the nation's social security system, which includes the pension and health care systems.

The latest set of estimates was reported to Monday's meeting of the population task force of the Social Security Council, which advises the welfare minister.

The young population, aged between zero and 14, is estimated at 8.98 million in 2065, down from 15.95 million in 2015. Their share of the total population is seen falling to 10.2 pct from 12.5 pct.

The number of people aged between 15 and 64, called the productive population, is also expected to fall, to 45.29 million in 2065 from 77.28 million in 2015, with their share sliding to 51.4 pct from 60.8 pct.

The elderly population is estimated at 33.81 million, almost unchanged from 2015. (Jiji Press)