Eugene Kapersky, founder of Moscow-based antivirus company Kapersky Labs, believes that within two or three years the volume of computer viruses on the Net will exceed the volume of legitimate e-mails.
The rapid growth in the volume and sophistication of computer viruses will leave the Internet exposed to attacks that could have devastating consequences for businesses, said Kapersky.
"If the capacity of the Internet is down by just 2%, the impact will be worse than 11 September in terms of business loss."
The recent Klez virus, the most virulent virus to date, hit 0.5% of the Internet, according to Kapersky's calculations, with more sophisticated viruses being developed all the time.
"There is going to have to be a change in the standards of the Internet," he said. "People will not be able to get onto the Internet unless they have some sort of ID card, a bit like a driver's licence." Under such a system people writing viruses would leave a trail pointing to their identity.
Kapersky said that large IT suppliers, such as Microsoft, will be forced to take the lead in developing new Internet standards, as the threat from viruses grows.
In 1991 there were only four types of viruses. This grew to five in 1995, and to between 20 and 30 in 2001. There are expected to be 35 different types this year.