A man who refused to delete sexual photos his teenage stepdaughter had sent her boyfriend because he wanted authorities to act has been convicted of possessing child pornography. 

Ashan Ortell, 57, was placed on the Australian sex offenders' register by a Melbourne court after he admitted to copying the photos to a USB stick, the Age reported.

Ortell had found the photos after confiscating his stepdaughter's phone. He reported the photos to school authorities and police, but was unhappy with their response and refused to delete them. Police subsequently raided his home and seized his computer and USB stick. 

While the judge acknowledged Ortell's lack of sexual motive, she noted that it was still a crime to possess sexual images of children.

"There is no suggestion of any exploitation of them by anybody. You made no attempt to conceal the images," she said. "In fact you were so concerned that you contacted the authorities about the images."

Ortell was handed a 12-month suspended sentence and will remain listed on the sex offenders' register for the next eight years.