The latest government policy to tighten second-home purchases is expected to further cool the housing market, but experts said it might be difficult to implement due to the independence of the country's housing registration and banking systems.

The policy, issued late on Friday, requires banks to ask for higher down payments and mortgage rates if one of the home-buyer's family members already owns property.

Even if an individual does not own any property at present, banks should also treat him or her as a second home-buyer if they have had a previous mortgage loan, the Ministry of Housing and Urban-Rural Development, the People's Bank of China and the China Banking Regulatory Commission said in a joint statement.

However, a manager with a commercial bank in Jinan of Shandong province, who wished to remain anonymous, said it is very hard for banks to decide whether the buyer and the family has had property or not.

"The housing registration system is not linked with the banking credit system nor the marriage registration system," he said. "At present, banks can only determine whether the buyer has taken a mortgage loan previously."

In many cases, a house is registered to a single owner instead of a married couple, so it is hard to heck whether the partner owns property, he added.

The new rule requires housing management authorities to produce a report on the property status of the family if they can. If authorities cannot determine the property status of the family, the person borrowing from a bank should offer a written statement regarding the family's housing situation.

A false guarantee will result in a negative credit record. But it remains unclear how a divorced person, who owns half of a house, will be treated when he or she applies for a loan for a second property.

In addition, because the housing registration systems in different cities are not linked with each other, it is hard to determine whether a buyer has bought any property in other cities, insiders said.

However, despite all these uncertainties, the policy may cool down the real estate market as buyers for self-use will watch and see, Wu Yijun, deputy general manager of the personal loan department of the Nanjing branch of China Merchants Bank, was quoted by Xinhua Daily as saying.

Deals at the Guangzhou property transaction registration center have already dropped about 20 percent since last month, though a change in the procedure at the center may have also delayed the transactions, Information Times reported on Sunday.

However, the cooling effect will not lead to massive closure of agents' offices, said Zhou Feng, manager of the research department of MyTopHome, a Guangzhou-based real estate website.

"The market should warm up again in a few months," said an agent surnamed Liu in Haizhu district, adding rentals are rising amid the lull in the pre-owned market.