Chongqing municipality will spend 100 billion yuan ($13.8 billion) over the next five years on the demolition and renovation of all old and dangerous houses in its nine urban districts, officials have said.

The mammoth project aims to build affordable housing for low-income residents, officials from the municipal government said.

The city's development and reform white paper revealed the ambitious plan. The 100 billion yuan investment is about a quarter of Chongqing's estimated gross domestic product for last year.

Zhou Bo, a spokesman for the municipal government, said the city will this year complete building an additional 1.8 million sq m of affordable housing for 30,000 low-income families.

Between 2004 and last year, 4.5 million sq m of such homes for 55,000 low-income families were built in the city.

Chongqing has about 7 million sq m of old and dangerous houses in its nine urban districts. The city currently has 160,000 low-income families who need decent accommodation.

Bo Xilai, Party secretary of Chongqing and former minister of commerce, said improving the urban environment is essential to people's livelihood.

A densely populated city like Chongqing has to build more clean and tidy public spaces for the common people, he said.

Huang Qifan, executive vice-mayor of the city, said earlier that the urban population in Chongqing will hit 10 million in a decade, becoming one of the six "super-large" cities of China along with Beijing, Shanghai, Shenzhen, Guangzhou and Tianjin.

Municipal plans placed the number of farmers turning urban residents in the next five to 15 years at 10 million.

International architects will also be recruited to help modernize buildings in the city in its quest to become an international metropolis, officials said.

Similarly, Guangzhou also plans to invest 1 billion yuan this year to meet the housing needs of low- to medium-income families, local authorities have said.

The pledge follows the offer made in Nov of government-funded low-rent housing or subsidies for 5,643 needy families, who had failed to meet the city's minimum living standard.

"We will spend a further 1 billion yuan on housing this year, which will not only benefit poverty-stricken families but also low- to medium-income families who can't afford a commercial apartment," Zhang Guangning, mayor of Guangzhou, said at a working conference on urban construction this week.

Jian Wenhao, director of the Guangzhou construction commission, said the city will improve the existing system for housing and work out a fiscal policy to support the system.