TOKYO (Kyodo) -- The number of people aged 65 and over in Japan with no close relatives is expected to grow about 1.5 times in 2050 to make up over 10 percent of the elderly population, estimates by a research firm have found.

Those without kin up to the third degree, including great grandchildren and great nieces or nephews, would total 4.48 million, the Japan Research Institute said, sparking concerns over who will act as their guarantors for hospitals and care homes and who will claim their bodies.

As fewer marry in the aging country, the number of people aged 65 and over with no relatives within the third degree is expected to increase from 2.86 million in 2024, according to the estimates based on data from the National Institute of Population and Social Security Research.

The projected figure in 2050 will constitute about 11.5 percent of the overall elderly population, or those aged 65 and older, at 39 million.

Japan's Civil Code places the onus on relatives within the third degree to support their aging family members.

Having a guarantor is crucial as many care homes and medical facilities require them for their services. Elderly people with no close kin and who are certified as needing long-term care or support under public long-term care insurance are forecast to rise from 340,000 to 590,000 in 2050, according to the estimates.

With a growing number of people without relatives using private care services, the government has taken steps such as drafting guidelines for firms to avoid potential issues.

The estimates also showed that the number of people aged 65 and up without children will increase from 4.59 million people in 2024 to 10.32 million in 2050. Within that group, the number of unmarried people is expected to rise from 3.71 million to 8.34 million in the same period.

In some cases, older people are also unable to rely on relatives due to their strained relationships. The Japan Research Institute's figures showed that the over-65s who cannot expect financial help from kin in an emergency are likely to rise from 7.9 million in 2024 to 8.9 million in 2050.