China's burgeoning elderly population poses a huge challenge for the country's social security system, with the economic cost of supporting senior citizens set to almost double by 2050, a senior official has warned.

The economic cost of supporting older citizens -- the ratio between spending on retirees and gross domestic product (GDP) -- will increase by 1.8 times between 2005 and 2050, said Gao Xiqing, vice-chairman of the National Council for Social Security Funds.

China's population is ageing much faster than other countries. In 2000, the country's proportion of people aged 65 and over was only half that in developed countries. But by 2050, China will have caught up, Gao said in an article published in the proceedings of the Boao forum held in southernmost Hainan Province.

Earlier reports said that China had nearly 144 million people aged over 60 in 2005, accounting for 11 percent of its population. The figure is expected to hit 400 million, or 30 percent of the total population, by 2050.

By then, contributions from two workers will be needed to provide for one senior citizen.

The exploding aging population will be a huge challenge for China's social security system, Gao said.

China established a nationwide social security fund in 2000. Even though it is now valued at more than 320 billion yuan (US$41.6 billion), Gao said it is not enough to fill the "pension gap".

Last year, China had 46 million retirees who received total pension payouts of more than 500 billion yuan (US$65 billion).

The fast aging society will also challenge the country's health and medical system, Gao added.

The government should improve social security investments and boost economic efficiency by stimulating consumption, he said.

Earlier reports said China became a graying society in 1999 when citizens aged over 60 exceeded 10 percent of the population for the first time. This was "too early" and has left China ill-prepared.

Developed countries started to age after they had carried out their modernization, when their per capita GDP was US$5,000 to 10,000.

China is aging before achieving affluence, with per capita GDP just over US$1,000. Developing economic muscle to deal with the aging issue is therefore a key priority.

(Xinhua News Agency April 21, 2007)