London: All Nokia smart phones need to be on a watch out now, as a malicious wallpaper programme which hijacks the main page of the 7610 handset is on the prowl.

In case downloaded, the software not only replaces all the icons on the 7610 phone with images of skulls, but also replaces many of the 7610's functions like contacts, calendar, notebook etc with non-working versions so the phone becomes almost useless.

The infected phones can only make and take calls.

According to the BBC, the file, nicknamed Skulls, is thought to have surfaced on shareware sites where people can pick up free add-ons, such as wallpaper, games and ringtones, for their phones.

The program is masquerading as software that creates new background images and themes for the main screen of the 7610 phone and is labelled as a file called: 7610.extended.theme.manager.zip.

A Finnish anti-virus lab F-Secure has produced guidance for users caught out to help them remove the program and get their phone working again.

Symbian phones produced by Sony Ericsson, Motorola, BenQ, Arima and Fujitsu are unaffected by the Skulls program.