A high-level security investigation has confirmed that a filthy text message was sent from the Norwegian prime minister's mobile phone.

The authorities claim that the message was sent in error by one of Kjell Magne Bondevik's chauffeurs.

The man dialled a wrong number and accidentally sent the rude SMS to 54 year-old Kari Stamnes in Trondelag.

The shocked woman told the Norwegian daily Dagbladet that the message was very dirty, and that she received no reply when she phoned the number to find out who had sent the text.

She tracked the number and was told that the message had been sent by a phone bought and paid for by the prime minister.

Oivind Ostag, an information officer at the prime minister's office, confirmed that the SMS was sent using one of its phones and said that it should not have been used for this purpose.