BEIJING - In a bid to cool down real estate speculation, officials are building a database, to be shared among 40 cities, where information about property ownership will be readily accessible.

"The shared database will involve two procedures," an official from the Ministry of Housing and Urban-Rural Development told the Beijing Times on Sunday.

"First, records about properties and their ownership would be sorted out and put into the database. Then information about earlier sales of properties will go online."

The database will reveal when people buy several properties in some of these 40 cities. Analysis of these records will show the money flow from one city to another, thus helping the authorities to supervise more closely the housing market in different areas and reduce speculation.

"This information-sharing system, which is a dream we have pursued for a long time, will play a positive role in controlling property bubbles. But it will take time to complete the system," Gu Yunchang, vice-president of China Real Estate Association, told China Daily.

He said there was no clear picture of the whole housing market, because there has been no national housing census since 1985. Besides, management of housing programs can only be traced on the Internet back to 2004 and records have been kept in different departments. So information on houses bought earlier is often incomplete.

Excessive growth in property prices could be cooled down in expanding cities on the second and third tiers, which have set various limits on house purchases, Gu said.

The government of Taizhou city, in East China's Zhejiang province, released a regulation on further control of the real estate industry on Aug 25, leading other second- and third-tier cities in the province to impose further limits on purchasing properties.

The regulation stipulated that families which planned to buy houses should apply for a properties check from the authorities, and they should have records of personal income tax or social insurance paid in the city for at least one year over the previous two years.

Housing prices in Taizhou have increased greatly in recent years, because hot money from surrounding cities which had already imposed purchase limits, such as Ningbo and Shanghai, flowed to the city, increasing the property bubble, according to a Xinhua News Agency report.

The Ministry of Housing and Urban-Rural Development has advised other second- and third-tier cities suffering increases in housing prices for similar reasons to impose limits on purchases in the near future.

"The ministry provides standards, which help cities judge whether they need purchase limits or not," Wang Juelin, deputy director of the policy research center under the ministry, told the Mirror Evening News on Sunday.

"Then the local authorities give feedback and release regulations according to their own situation."

More than 20 second- and third-tier cities have decided to impose purchase limits and more cities are likely to follow them. The whole process will be finished by the end of August and local governments may release their regulations in September.