DPP challenges SA child sex sentence

The sentence imposed on an Adelaide childcare worker who used four young children as "his sexual playthings" was manifestly inadequate, an appeal court has been told.

Mark Christopher Harvey was jailed for a further two years in July, a sentence described by the Director of Public Prosecutions, Adam Kimber SC, on Thursday as unreasonable and plainly unjust.

The 43-year-old was found guilty of persistent sexual exploitation of four primary school-aged children between 2007 and 2011 when he was director of an Adelaide after-school care program.

His matter sparked a royal commission into the SA Education Department's handling of school sex abuse cases.

When Harvey went to trial, he was serving a six-year jail term for unlawful intercourse with a child on a date after the other offences.

In his Court of Criminal Appeal challenge, Mr Kimber acknowledged that the offending against the four children was at the lower end of seriousness.

The trial judge had found that Harvey obtained sexual gratification by sucking the toes of the children, which they had believed was "all in play".

But Mr Kimber said the "unique" nature of the physical acts should not be allowed to obscure the insidious impact of the offending on the children, the families and the school community.

"He was advancing his own perverted sexual interests on the children .. using the children as his sexual playthings," he said.

Mr Kimber noted the number of children involved, the persistent nature of the offending, the fact that Harvey was in a position of trust and the need for general and personal deterrence.

The sentencing judge added the two year term to the six years Harvey was already serving.

His new non-parole term was set at three years three months, meaning he will be eligible for release next May.

The hearing is continuing.