TOKYO (Reuters) - Japan's population is expected to decline by 30 percent to below 90 million people by 2060, with two out of every five people aged 65 or older, a government agency said, underlining the financial burden on one of the world's fastest-ageing societies.
Prime Minister Yoshihiko Noda has vowed to double the 5 percent sales tax in two stages by October 2015 to help fund bulging social security costs, which are rising by 1 trillion yen ($13 billion) every year and aggravating a public debt already twice the size of Japan's $5 trillion economy.
But the biggest opposition party, although agreeing about the need for a tax hike, is threatening to block legislation in parliament's upper house. The opposition argues that the ruling Democrats' plan to revamp public pensions would require a higher levy than currently planned.
"The trend of the ageing society will continue and it is hard to expect the birth rate to rise significantly," Chief Cabinet Secretary Osamu Fujimura told a news conference. "Thus, comprehensive tax and social security reform is needed."
Japan's population is ageing at the fastest pace among developed countries due to a low birthrate and long life expectancy.
The population is expected to fall below 100 million in 2048 and dip further to 86.74 million by 2060, from 128.06 million seen in 2010, according to a projection by a research arm of the health ministry released on Monday.
By 2060, the number of people aged 14 or younger is forecast to fall by more than half, to 7.91 million.
By contrast, the population of those aged 65 or older is seen rising 18 percent to 34.64 million, accounting for 39.9 percent of the entire population, compared with 23.0 percent estimated in 2010.
The fertility rate, the expected number of children born per couple, is expected to reach 1.35 in 2060 from 1.39 seen in 2010, below 2.08 needed to keep the population from shrinking and compared with the global rate of around 2.5.
The estimate also showed that the average life expectancy will rise by over four years in 2060, to 84.19 for men and 90.93 for women.
The population projection is compiled roughly every five years based on data including a census and demographic statistics and serves as reference materials for government's social security policy.
($1 = 76.7350 Japanese yen)
(Reporting by Tetsushi Kajimoto; Additional reporting by Kaori Kaneko; Editing by Chris Gallagher)