China had "basically" established a social security network on the foundation of social insurance, social assistance and social welfare by the end of 2011, the country's auditing authority said Thursday.

The National Audit Office said in an audit report posted on its website that more than 1.3 billion people were covered by the social insurance network by 2011, 3.77 times the number of people covered in 2005.

A social assistance network that mainly includes subsistence allowances for urban and rural people living in poverty has realized full coverage in the country, the report said.

"China has gradually improved the social welfare system that prioritizes assistance for the elderly, the disabled and orphans," it said.

By the end of last year, China had 42,500 social welfare institutions with 3.21 million beds, and a total of 2.38 million elderly people, disabled people or children were accepted.

The report also said that the fund for China's social security system was basically guaranteed and a management system for its social security net had also basically come into form by 2011.

"The social insurance fund comes mainly from premiums paid by employers and individuals as well as from fiscal revenue, while the fund for social assistance and welfare is mainly from revenue," the report said.

The income of 18 items of social security funds in 2011 was 2.84 trillion yuan (448 billion U.S. dollars), up 312.79 percent from 2005, while the expenditure rose 299.78 percent from 2005 to 2.11 trillion yuan.

The total surplus of social security funds stood at 3.11 trillion yuan by the end of 2005, surging 435.24 percent from 2005, according to the report.

"China has established a social security net that covered the largest population in the world by 2011," the NAO said.

The social security network has effectively promoted social equity, improved people's livelihoods and promoted social harmony and stability, the report said.

This is the first time China has conducted a thorough audit of its social security network.

Chen Taihui, head of the NAO's social security auditing department, said the auditing process for the first time dug into the details of China's social security system.