New computer software which, once installed on a mobile phone, can be used to eavesdrop conversations and record text messages, has been sold online recently and is in great demand, Thursday's Daily Sunshine reported.

The software, dubbed "your personal undercover agent," is said to be able to track all the conversations through a mobile, as well all text messages from and to the phone, the newspaper said.

Its functions also included added security for the phone on which it is installed to prevent theft of personal information and counter attacks by other software, according to the newspaper, citing a software manual on a distributor Web site. The newspaper didn't disclose the Web address.

The report said an upgraded version of the software has recently been released which enables long-distance eavesdropping.

A person who has purchased the software and installed it on another person's mobile can also, without being noticed, activate the mobile's inner microphone to hear what its carrier is doing.

An employee of the software developer who declined to give his name said the product is very popular. "We have 16 distributors nationwide so far. Feedback from our three Shenzhen distributors is also amazingly good."

A man surnamed Long whose company started selling the software products two weeks ago said most of his clients had bought it for personal use. "They said they are private detectives and are using it to investigate extramarital affairs," Long said.

The regular version of the software costs some 400 yuan (US$52) to 600 yuan depending on the quantity. A higher price is charged for the upgraded version at 1,380 yuan, which also includes unlimited after service and free upgrades.

Despite its popularity, the emergence of the software has aroused wide concern over privacy and personal security. "If someone with malicious intentions installed it on my mobile, I would be afraid that all my clients' information on the phone and some confidential commercial secrets would be exposed. That would cause me substantial economic losses," said a man who gave only his surname Zhang.

However, there is so far no relevant law forbidding the development and sale of such software in China, said Wu Xiaorong, a lawyer with Guanghe Legal Service Firm. But Wu said the application of such software will result in violation of privacy.

So far, the software can be applied to 13 Nokia and two Samsung mobile phone models.

Editor: Yan