The number of Japanese aged over 90 has passed two million for the first time, according to the latest government data.
The figure has doubled from 1.02 million in 2004 to 2.06 million.
The total number of elderly Japanese - over 65s - comes to 35.14 million, accounting for 27.7% of the population.
The data, released for Respect for the Aged Day on Monday, highlights the issues posed by Japan’s declining birth rate, which is already affecting the country's economy in areas including the job and housing markets.
According to Japan’s Ministry of Health, Labour and Welfare, the number of births dropped to below one million for the first time in 2016.
The country’s current population of 127 million is expected to decline by nearly 40 million by 2065, Japan’s National Institute of population and Social Security Research said.
Experts say Japan’s shrinking population can be attributed to young people focusing on their careers and abstaining from sex and marriage, while senior citizens are living longer than ever.
A study released earlier this year found nearly a third of Japanese people are entering their 30s without any sexual experience.
The recent population data highlights the contribution of senior people to Japan’s economy.
It found record 7.7 million people aged 65 or over had a job as of last year, of which 3.01 million had part-time or temporary jobs.
“Elderly people are eager to work and more companies are accepting them,” a ministry official in charge of the statistics said.
Some doctors and academics have proposed Japan redefines the term “elderly” to refer to people over 75, rather than over 65, because of the country’s widespread longevity.
