More than one million computer systems have fallen victim to the Blaster/Lovsan worm since it emerged in the wild last week.

Infections are continuing to spread at a steady rate, with the worm taking over 30,000 systems per hour during peak times, experts have warned.

According to data collected by Network Associates' Hackerwatch.org, at least 1.2 million unique source IP addresses have been infected.

A detailed graph of the worm's progress can be found here.

Since the worm spreads quietly and does not arrive as an email attachment, users may not immediately realise when they have been infected.

The first sympton they may spot is excessive use of home broadband connections.

Network Associates said in a statement: "This worm has infected over one million users in a remarkably short period of time, and highlights the need for PC users to make sure they have comprehensive and constantly updated antivirus and personal firewall solutions on their machines to prevent future attacks from these types of internet threats."