Several mainland ministries are forming a united front to investigate possible collusion between Shenzhen authorities, property developers and real estate agents, amid mounting official concern, Guangdong media reported yesterday. A senior Shenzhen government official was quoted by this week's Nanfang Weekly as saying property prices were 'the biggest political problem in Shenzhen'. Representatives from the ministries, including construction, land and resources, will arrive in Shenzhen in September to investigate whether any officials have imposed arbitrary charges, abused their rights, taken bribes or illegally approved development and construction plans, the Southern Metropolis News reported. The team would also check whether Shenzhen's developers had been involved in illegal practices. They would also investigate whether property agencies had embezzled escrowed money from buyers, bid up property prices, bribed officials or swindled clients. May data showed Shenzhen again led the nation in property price increases, with average residential prices rising 12.3 per cent year on year to 14,223 yuan per square metre, despite efforts to rein in the sector. Wang Feng, director of Shenzhen's Real Estate Research Centre, said the city government had, over the past month, asked 3,677 developers and agencies to examine their own activities and report back. As a result, about a dozen had licences cancelled and 52 had been asked to change their business practices. Mr Wang said officials from 13 departments including the land, audit, tax and commercial authorities, were also required to conduct a self-assessment between June last year and March next year. Andy Lee Yiu-chi, general manager of Centaline China's Shenzhen branch, said it would be hard to evaluate the effect of the campaign but its main impact on Shenzhen's market would most likely be psychological. 'There are similar audit and inspection campaigns each year,' Mr Lee said. 'I see little difference this time.' But he said the frequent release of market tightening measures in recent months would encourage more investors to adopt a wait-and-see approach.