Tokyo  - Japan's Health Ministry said Friday that 40,399 of its citizens will be aged 100 years or older by mid-September, an increase of more than 10 per cent year-on-year.

The figures of the annual survey show the increase of centenarians has accelerated as it took only 2 years for the number of centenarians to grow from 30,000 to 40,000.

Previously it took four years for the number of 100-year-olds to grow by 10,000 to 30,000. In 1998, there were only 10,000 Japanese aged 100 years or older.

Japan has the world's highest average life expectancy at 85 years. Scientists say one reason many Japanese reach a ripe old age is the healthy traditional cuisine, favouring fish, vegetables and rice.

The island's oldest woman is aged 114 and lives in Okinawa prefecture in southern Japan, which also has the most centenarians. The oldest man is 112 years old and lives in Kyoto prefecture.

In real terms the population of the world's second-largest economy is shrinking and greying at an ever faster pace as rising life expectancy combines with shrinking birth rates. (dpa)