In August, the Justice Ministry ordered a review of records that found about 77,000 people who would be at least 120, and 884 people who would be 150 or older. The head count followed a flurry of reports about how elderly people are falling through the cracks in Japan as its population ages rapidly and family ties weaken.
In all, the survey of family registration records nationwide found that 234,354 centenarians were still listed as alive, but their whereabouts were unknown, the ministry said.
Because listings of people over 120 are almost certainly the result of lax bookkeeping, the ministry instructed local offices to attach a note to those records saying the people were unaccounted for, a ministry official said.
A ministry official said many of the missing people had probably died, lost touch with relatives or moved overseas. The official spoke on condition of anonymity, citing ministry policy.
In late July, police discovered that Sogen Kato, who would have been 111 and was thought to be Tokyo's oldest man, had actually been dead for 32 years and his decayed body was still lying in his home.
Police have arrested his granddaughter for suspected abandonment and pension fraud.
That case and other revelations of scamming relatives and isolated and forgotten elderly people led to closer scrutiny ahead of the Health Ministry's annual report on centenarians. Last year's report said Japan had 40,399 people aged 100 or older with known addresses.
An official at the Health Ministry's statistics bureau said Friday's survey does not change Japan's status as a fast-aging nation because life expectancy calculations are not based on family registration records.
The share of the population aged 65 and older hit a record high of 22.7 percent last year, while young people aged 14 or younger fell to 13.3 percent - the lowest among 27 countries with populations of more than 40 million. Japanese women can expect to live 86 years, the longest in the world, and men nearly 80.
The graying of Japanese society and its low birth rate have brought an increasing number of social problems, strained government services and pension programs, and raised worries about expected labor shortages in the near future.