Japanese women have fallen behind Hong Kong in global life expectancy rankings for the first time in 25 years.
This was partly due to the devastating earthquake and tsunami that hit the country in March 2011, said an annual report by Japan's health ministry.
The expected lifespan for Japanese women dropped from 86.30 years in 2010 to 85.90 years in 2011.
The official life expectancy for women in Hong Kong last year was 86.70 years.
Japan has topped the women's rankings for a quarter of a century, with longevity attributed in part to a healthy traditional diet.
The magnitude 9.0 earthquake and tsunami that left more than 20,000 dead or missing pushed the life expectancy down.
However the report noted that even without the disaster Japanese women would still have dropped behind Hong Kong in the statistics.
Other factors contributing to the dip included a rise in the number of suicides among Japanese women, disease and other natural death causes, the report said.
The life expectancy for men in Japan also declined from 79.55 in 2010 to 79.44 last year.
The men dropped from fourth place in 2010 to eighth last year in the global life expectancy ranking, said Japan's Kyodo news agency.