THE next pieces of hi-tech equipment set to be the target of virus writers are mobile phones and handheld computers.

Experts believe that it will only be a couple of years until a malicious program is designed that will attack portable devices.

Viruses have already been created that exploit vulnerabilities in mobile phones and handheld computers. Most of them have been harmless.

A virus appeared for the Palm handheld computer called Liberty, which tried to delete all the applications stored on the gadget, but could not spread from Palm to Palm.

And more problems could be on the way as mobile phone companies offer 'always on' connections ensuring customers get their e-mail and text messages as fast as possible.

These constant connections could be exploited by viruses to spread much more quickly than they would if phones connected to data networks more intermittently.

And if the outbreak reached the severity of some desktop computer viruses such as the Love Bug it could cost telecommunications firms billions to clean up.