Although the majority of mobile phone users have backed a new policy that requires them to register their real names, some of them are worried the rule, which came into effect nationwide on Wednesday, may violate their privacy.

While more than 80 percent of those surveyed showed support for the real-name registration system for mobile phone users, 34.6 percent expressed worries that their personal information could be leaked and abused, according to an ongoing online poll conducted by Chinanews.com. The results are based on the opinions of 6,237 people who participated in the poll.

"The procedure of registration does not bother me. But I am really concerned about any leakage of my personal information," said Zhao Chen, 27, a Beijing resident. "If I have to register with my ID, it just feels I will be watched whenever I use my phone."

In June, five employees of a Beijing telecom operator were charged with illegally obtaining, supplying and selling clients' call records to private companies, Mirror Evening News reported.

The new policy, intended to crack down on spam, may not achieve its desired effects, warned Zhang Pei, an assistant lawyer at the Guangzhou-based Mumianhua Law Firm.

"ID registration for mobile phone users will not necessarily eradicate or reduce spam, because a considerable amount of spam is sent out by telecom operators, while this new policy has no restriction on the operators," Zhang said.

Moreover, some mobile phone users worry that the new regulation could lead to more crimes, as fraudulent text messages will look more deceptive.

"In the past, when I received text messages that said my son was sick so I need to transfer money to his friend's bank account, I could tell it was a scam and ignore it because the message did not address me clearly," said Zhang Lan, a Shanghai resident.

"If scammers get their hands on my personal information and address me exactly the way my son's friends would, I would not know if it is a scam or not," she said.

People from China's three major cities - Beijing, Shanghai and Guangzhou - have showed little enthusiasm.

Beijing's roadside newspaper stands have been banned from selling SIM cards. Violation of the ban could result in a 5,000-yuan ($734) fine, Beijing News reported on Wednesday.

Even as the new rule went into effect, prepaid mobile phone numbers were being sold at grocery stores and newspaper stands in Shanghai on Wednesday and buyers were not asked to present their IDs.

Currently, retailers of SIM cards do not have to ask buyers to register with their ID cards, as detailed documents on the implementation of the new policy have yet to be released, according to a clerk at the Shanghai Municipal Communications Administration who spoke on condition of anonymity.

"Buyers can just put down their ID number, if they remember, in my notebook," said Yang Chunfen, who sells about 50 prepaid mobile phone numbers every day, "So far, only one person has left his ID information."