A man who kept sexts sent between his teenage stepdaughter and her boyfriend because he wanted police to act has been convicted of possessing child pornography and placed on the sex offenders register.

In a case that could have consequences for parents concerned about sexting, the 57-year-old man was sentenced in the County Court this week after admitting to copying the naked images on to a computer and USB stick.

A man who kept sexts sent by his teenage stepdaughter to her boyfriend was convicted under child porn laws. Credit:Stocksy

Despite warnings he could be prosecuted, the man kept the pictures because he was not satisfied by the response from police and the girl's school. He had informed them about the sexual photos his stepdaughter had sent to her boyfriend.

After refusing to delete the pictures, the man's computer and USBs were seized in multiple raids by police in 2013. They found 18 images on the devices.