At least 20,000 police surveillance cameras are being installed along streets in southern China and will soon be guided by sophisticated computer software from an American-financed company to recognize automatically the faces of police suspects and detect unusual activity.

Starting this month in a port neighborhood and then spreading across Shenzhen, a city of 12.4 million people, residency cards fitted with powerful computer chips programmed by the same company will be issued to most citizens.

Data on the chip will include not just the citizen's name and address but also work history, educational background, religion, ethnicity, police record, medical insurance status and landlord's phone number. Even personal reproductive history will be included, for enforcement of China's controversial "one child" policy. Plans are being studied to add credit histories, subway travel payments and small purchases charged to the card.

Both steps are officially aimed at fighting crime and developing better controls on an increasingly mobile population, including the nearly 10 million peasants who move to big cities each year. But they could also help the Communist Party retain power by maintaining tight controls on an increasingly prosperous population at a time when street protests are becoming more common.

"If they do not get the permanent card, they cannot live here, they cannot get government benefits, and that is a way for the government to control the population in the future," said Michael Lin, the vice president for investor relations at China Public Security Technology, the company providing the technology.

But rising fears of terrorism have lessened public hostility to surveillance cameras in the West. This has been particularly true in Britain, where the police already install the cameras widely on lamp poles and in subway stations and are developing face recognition software as well.