Eight out of ten children under the age of two have their pictures online via sites like Facebook, raising privacy and even paedophilia concerns, an Internet security company said today.

A study by Melbourne-based AVG found an average of 81 per cent of toddlers in ten western countries have a digital presence; 92 per cent in America, followed by 91 per cent in New Zealand and 84 per cent in Australia and Canada.

A third of children are online at just a few weeks of age, while a quarter appear on the Web before they are even born in the form of ante-natal scans, the company said.

"It's a sobering thought," said managing director Peter Cameron. "The vast majority of children today have online presence by the time they are two years old, a presence that will be built on throughout their whole lives."

"It reinforces the need for parents to be aware of the privacy settings they have set on their social network profiles. Otherwise, you may be sharing your baby's picture not only with your friends and family but with the whole online world."

The company said parents should keep tight privacy settings to guard against identity theft or unauthorised use of the pictures which could dog the child as it grows up.

"They've got to have (settings) so they are only sharing with family and close friends and it's kept within close confines, otherwise it can be picked up and used anywhere," said spokesman Lloyd Borrett.

"Stranger danger applies online just as much as it does in the real world."