OVER HALF the photos found on pedophile websites are taken from social networks such as Facebook and Instagram, according to Australia's new Children's eSafety Commissioner reports The Week.

Investigators looking into complaints of child sex abuse have uncovered "tens of millions" of photos of children doing everyday activities such as swimming, sports or homework, Alastair MacGibbon told the Sydney Morning Herald.

While not sexually explicit, the innocent images were sexualised through added comments, or presented in folders named thematically such as "my daughter's Instagram friends" and "nice boys play in river", said MacGibbon.

Many of these images were posted unwittingly by "over-sharing" parents, apparently unaware of how easily they could be downloaded by strangers.

Toby Dagg, senior investigator at the Office of the eSafety Commissioner, told the Herald they had uncovered one site with over 45 million images with "about half the material sourced from social media".

The revelations come after a 2013 investigation uncovered one site with over 100 photos of children opening Christmas presents.

"Within ten days [of] being uploaded, some of the content had been viewed over 1.7 million times, often accompanied by highly explicit and very disturbing user comments," MacGibbon said.

Although all the recent content was found to be hosted outside of Australia, roughly 90 per cent of images investigated by the eSafety hotline were "removed in less than three days", according to the Daily Mail.

In partnership with Australian law enforcement and an international network of internet hotlines, the investigation has so far resulted in the removal of images depicting more than 25,000 children.

Facebook has repeatedly defended its safety and security settings, encouraging parents to set up limited locked groups to share images with friends and family.