The black market in Beijing household registrations is likely to continue despite a crackdown by police who detained a gang involved in the trade, say experts.

The gang allegedly pocketed more than 3 million yuan ($486,000) by exploiting hukou, the household registration system. They helped 80 university graduates to obtain documents even though they were not eligible, say police.

The Beijing procuratorate approved the arrest of 13 people on suspicion of selling official documents and abusing power.

The police learned of the gang's activities from an online article that talked about the sale of Beijing hukou eligibility for 300,000 yuan, and targeted a suspect surnamed Tian.

Police believe Tian, the manager of an information technology company, colluded with employees of the personnel departments of State-owned enterprises and high-tech firms to help graduates obtain hukou eligibility.

The graduates were allegedly charged varying amounts ranging up to 330,000 yuan.

Police detained Tian, 42, on July 15 and the other suspects were arrested on Aug 18.

Beijing police have vowed to crack down on the sale of hukou eligibility and detect, investigate and severely punish those involved, according to a statement issued to China Daily.

The number of people who can legally obtain Beijing hukou is limited. Most civil servants and employees of State-owned enterprises in the capital are eligible, as are graduates who receive assistance from recruitment companies.

Zhai Zhenwu, head of the School of Social and Population Studies at Renmin University of China, said the black market has existed for a long time and is unlikely to disappear because of the high demand.

There are 8 million migrants in Beijing, but over the past decade only 180,000 have been granted hukou on average each year.

Zhai said people buy hukou illegally because it brings many benefits. It gives the holder access to advanced social welfare and can help their children to enter elite universities more easily than other young people.

The State Council last month announced plans to reform the hukou system. Large cities such as Beijing will operate a points system — similar to the green card application process in the United States — to standardize procedures for granting residence permits to the migrant population.

Zhai said the reformed system will not be able to meet the demand as the number of registrations issued will still be limited. This means there will continue to be opportunities for black market traders.

Lu Jiehua, a professor of demography at Peking University, agreed that the hukou black market is likely to continue in Beijing.

"It's possible that the price on the black market will rise in the future," Lu added.

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