Cellphone customers in China must provide identification from Wednesday to purchase a new number, state media said - the latest step by Beijing to tighten curbs over the world's largest mobile market.

The new regulations also apply to foreigners and those wishing to purchase a pre-paid SIM card, the China Daily and Global Times reported, citing sources at the Ministry of Industry and Information Technology (MIIT).

Those with existing mobile subscriptions will be asked to register with their carriers before 2013, or their plans could be cancelled, the Global Times said, citing MIIT official Chen Jinqiao.

Street newspaper stands will be banned from selling SIM cards until the owners are trained on how to register customers, the reports said.

The new rules are part of the government's efforts to prevent spam, pornographic messages and rampant fraud through the country's vast mobile network, MIIT spokesman Wang Lijian told the China Daily.

Officials at the ministry declined immediate comment.

The government planned to carry out nationwide registration of mobile phone users as early as 2006, but the plan did not come to fruition as telecoms operators and users showed little interest, the report said.

China had 814 million mobile phone users at the end of July, official data showed.

But as many as 320 million users have not provided identification, Chen told the China Daily.

A report issued by a government-linked body in April said about 75 percent of China's roughly 200 million web users under the age of 25 use their mobile phones to access the Internet.

Beijing blocks access to any web content that the government deems unacceptable, ranging from pornography to political dissent, under a vast system of censorship known as the "Great Firewall of China".