The man cannot be named as he was a juvenile on October 12 , 2008, when he punched Louise in the face.

The court heard that the girl had been screaming when the juvenile told her to shut up, and then assaulted her.

He hit her so hard that Louise fell to the ground from the chair she had been sitting on.

Louise disappeared later that day and her body, which had been stuffed into a wheelie bin, was unearthed in February 2011 in the backyard of a northern Illawarra home.

The man and his mother were arrested in March 2011 and charged with being accessories after the fact to manslaughter.

A jury found them guilty in July last year and he was sentenced to three years and eight months in prison, which was backdated to March 2011 when he was first taken into custody.

His non-parole period expired in December last year and he has been under supervision ever since.

The man's assault charge was dealt with separately to the charge relating to covering up Louise's death.

Judge Paul Conlon noted the man had been doing well since his release from jail, making his first attempt at formal education by studying a diploma of business.

He sentenced the man to a 12-month good behaviour bond, which will expire in May 2015.