Japan's rapidly-aging society will see a quarter of its breadwinners turn 75 or older by 2040, the Nikkei daily has reported, citing a study from the National Institute of Population and Social Security Research.

The total number of head-of-households who are 75 years of age or more will mount to 12.17 million by that year, while the number of single-person households will climb to 19.94 million, or two-fifths of the total, the report said. The number of people living alone who are 75 or older will top 5 million, it said.

As the number of elderly Japanese people living by themselves increase, the country is increasingly in need of a revamp of its social security system and relevant infrastructure, the report said.

The government has been opening the door to more low-skilled foreign workers as the rapidly aging population fuels a labor shortage. With unemployment at just 2.3 percent, near the lowest since the early 1990s, labor shortages are being felt in a range of industries from convenience stores to construction before the Tokyo Olympics next year.