Google has provided a US child-protection group with image recognition technology to help catch people who prey on children.

Analysts at The National Centre for Missing and Exploited Children (NCMEC) had been overwhelmed by milllions of pornographic images and videos of children, but are now using Google software to streamline their workload.

Organisations working to protect children must keep up with the criminals, said Ernie Allen, president and chief executive of NCMEC.

"Criminals are using cutting-edge technology to commit their crimes of child sexual exploitation, and in fighting to solve those crimes and keep children safe, we must do the same," he said.

"That is why we are so grateful to Google for providing new tools that will enable us to better serve law enforcement in battling exploitation and rescuing children."

The technology will help analysts search NCMEC's systems and sort and identify files containing images of child pornography victims, creating an automated process that allows experts to compare the images and videos.

The video tools will streamline analysts' review of video snippets from files seized in child pornography cases.