China's supervision officials on Thursday warned that land management and construction approval authorities had become high-risk posts where officials were vulnerable to bribes.

Corruptions could occur in all links in the chain of a construction project, from land use approval to project management, public bidding and construction material purchase, Hao Mingjin, vice minister of supervision, told a press conference held by the State Council's Information Office.

Hao cited 20 criminal cases in his opening remarks to the conference, in which officials in charge of land management and state-run construction companies were penalized.

A total of 5,241 officials received the Communist Party's disciplinary penalties and 3,058 were transferred to judiciary procedures for corruption or misconduct related to construction projects, according to Hao.

Behind frequently exposed construction quality scandals in China, government officials were found taking bribes, in the forms of cash, gold, houses, luxury cars and stocks, among others.

Among the twenty corruption cases, the biggest amount of the bribe was more than 22 million yuan (US$3.2 million), and the vice minister admitted that the average bribe amount in construction cases was much higher than those in other cases. Fu Kui, a director with the ministry, said land management authorities monopolized both administrative approval and administrative law enforcement, while supervision and management regulations were not sufficient, which explained partly why officials in relevant departments were vulnerable to corruption.

As land for real estate projects was a scarce resource but the demand for that was soaring, the gap offered an opportunity for those officials who can't resist temptation to exchange the public resource for personal gains, according to Fu.

Fu said the government would continue reforms in land management by reducing administration involvement in the industry, introducing more supervision and promoting a more market-orientated practice.

The Communist Party of China has issued a special regulation to prevent Party and government officials from abusing their powers to gain personal benefits from construction projects.