Yancheng in Jiangsu published a similar regulation, saying the "unusual leaking of property ownership registration information … had caused concern to some residents".

Several real estate agents told the that searches for property ownership information in Guangzhou had been restricted in January and only married couples could now search for such information.

"The search must be approved in writing by the property trade centre if the search shows someone has more than three properties registered under his name. Only approved applicants can be shown the results," one agent told the newspaper.

The reports generated widespread criticism online, with many calling the rules a protective umbrella for corrupt officials.

A regulation introduced by the Ministry of Housing and Rural-Urban Development in 2006 allows the public to inquire about property ownership by individuals and companies, but the Law on Property which came into effect a year later restricted inquiries to "interested parties". However, with restrictions on purchases imposed in many cities, it was not uncommon for property trade centres to allow searches for the number of properties registered under one name.

Corrupt officials often purchase property to hide illegal income, and political commentators said such regulations would be a blow to anti-graft efforts, especially those initiated by unofficial parties.

"It's only natural that people connect such bans with attempts to muzzle the exposure of corrupt officials after several online exposés led to official investigations," said Professor Pu Xingzu, of Fudan University's school of international affairs and public relations.

A senior urban management official from Guangdong, now known as "Uncle House", was sacked in October after investigators found he and his family had acquired 22 homes despite their meagre income. A 22-year-old woman from Zhengzhou , Henan , earned the nickname "Sister House" after 31 homes were registered under her family's name. Her father, a local urban management official, was removed from his post.

Pu said the regulations also backpedalled on Communist Party leader Xi Jinping's pledge to clean up the party and step up the fight against graft.

Professor Ren Jianming , of Beihang University's school of public administration, said such regulations effectively protected the privacy of corrupt officials, following years of unanswered calls for the public disclosure of officials' assets.

Officials at county level or above have started declaring assets, but only to their superiors, not the public.

"The perspective of protecting officials' privacy should give way to protection of public interest," Ren said. "Stressing protection of privacy without a system to declare officials' assets and protect the overall public interest will only generate discontent."