All mega cities, including Beijing, Shanghai and Guangzhou, are to impose further controls on population growth in line with the State Council's latest guidelines on household registration reform.

More cities will adopt credit systems similar to the points-based method used by the UK to decide whether applicants qualify for visas.

"For mega cities with populations of more than 5 million, the guidelines clearly require tighter control on population increases," said Huang Ming, deputy minister at the Ministry of Public Security.

"To make the household registration system more transparent, a credit system will be established."

The household registration system, or hukou, determines whether a citizen qualifies for legal residency in a city. Residency brings with it access to health and welfare services and the education system.

Some large cities such as Shanghai and Tianjin, and a number of cities in Zhejiang and Guangdong provinces, already use credit systems to standardize the procedures used by migrants to apply for residency.

Under the UK system they are modeled on, points are awarded for various criteria such as the ability to fund an initial stay and speak the language. A certain number of points must be attained in order to settle in the country.

Now more mega cities are to adopt a similar approach.

"Beijing and other cities will carry out the instructions from the central government and introduce a localized point system for household registration as soon as possible," said Huang.

In the past decade, metropolitan areas with more than 10 million residents, such as Beijing, Shanghai and Guangzhou, have all experienced an average annual growth rate of half a million, said Huang.

"The pressure is too high," he added. "Strictly controlling population growth in mega cities is a policy based on the state of our country and the practical concerns of the extra-large cities."

Chen Mengwei contributed to this story.