Technology experts have warned that bluetooth phones are vulnerable to hacking, allowing hackers to steal phone-book data and text messages and even turn the mobiles into bugs to listen to conversations secretly.

"Serious flaws discovered in bluetooth technology used in mobile phones indicate that a hacker could download contact information from victims' address books, read their calendar appointments or read text SMSs on their phones to conduct business spying," the source said.

A hacker can even place false text messages in a mobile phone's memory, or turn the victim's phone into a listening device to receive private conversation in the immediate vicinity of the mobile, and most of these transgressions can be done without leaving any trace. Another risk is that the worm arriving on the phone as a bluetooth message will have to be automatically accepted by the user.

"I received such a trapped message without realising that it is harmful," Mohammed Ali, an expatriate living in Al Ain, said.

Another user, Nada Osman, warned against opening SMS messages coming from unknown sources.