A teacher's suspension after his arrest for sex offences allegedly involving a student has been highlighted as the South Australian Opposition keeps pushing the issue of child protection.

Education Minister Jennifer Rankine said last July that her office was notified immediately and the school involved wrote to parents.

She said at the time she was satisfied the Education Department acted promptly.

The teacher allegedly involved was suspended without pay.

Opposition education spokesman David Pisoni has now raised the case as what he calls another example of failures in the child protection system.

"There is no doubt that what has been exposed over the last 12 months is a Government and a department that has been hell-bent on keeping any bad news quiet," he said.

Ms Rankine agreed the matter was concerning but said the Opposition again was playing politics with the issue of sexual abuse of children.

"A teacher has been arrested, he was arrested in July this year and in July this year parents were notified," she said.

"Notification went out to those people who needed to know to ensure that they could protect their children, do what they needed to do for their children."

The suspended teacher was charged with trying to lure students into being open to sexual activity.

The case is at the same school where another matter is now under investigation.

The teacher in that earlier case, in 2004, later moved to an Adelaide school and was stood down with pay only last week when the matter became public.

It was alleged that teacher used a student's computer login to view pornographic websites.

The wider issue of child safety in schools led to a royal commission in South Australia.

Among its findings was criticism of how education authorities responded to abuse allegations.

There is now a new head of the Education Department and the departmental structure remains under review.

A parliamentary inquiry also is taking evidence over the handling of abuse allegations.