Armed with a hidden tape recorder, a mother induced a man with whom her son was working to admit he was molesting the boy, a magistrate heard yesterday.

The man admitted he sexually exploited the 12-year-old boy and will be sentenced tomorrow.

The 40-year-old married man - with two children of his own - was arrested last August after the "sting operation".

The stunned woman wrote in a victim impact statement read out before Magistrate Will Francis: "Why did I think this man was an angel sent from heaven? I knew it was strange and too good to be true. Why did I let this happen? Why didn't I see this coming and do something about it ?"

She added: "Someone had to come forward and I wish it had happened a long time ago. This monster has to be stopped. He can't be continually allowed to get away with this."

The statement went on to describe the man as a "very, very sick man" who should "not be allowed to roam the community preying on innocent children. He should have no contact with children. He should be branded for life".

The man pleaded guilty to sexual exploitation of a young person while in a position of trust at a court appearance earlier this week. Crown counsel Charmaine Smith said the victim - now 14 - said he did not want to tell his mother about the incidents because he didn't want to upset her.

"The more I wanted to tell her the more it hurt," he said in his victim impact statement. He added that his school work suffered and that he was terrified at the idea of having to testify in court.

The boy continued: "When he first pleaded not guilty I was very upset to see the look on my mother's face. When he was asked to plea again it was very relieving to hear he pleaded guilty. The thought of what happened to me will haunt me for the rest of my life. I don't wish it on anyone else."

The court also heard that between May and June last year while he was working with the victim, the defendant tickled the victim all over his body including his private parts and buttocks and made attempts to kiss him on the lips.

The boy's mother questioned her son about the nature of the relationship and her suspicions were further aroused when the boy responded with defensiveness and denials.

She then arranged to meet with the man armed with a tape recorder and the man eventually admitted hugging and kissing her son and touching his private parts.

But the mother had to arrange another meeting when she realised that the conversation had not been properly recorded.

The defendant again admitted the relationship during a second conversation with the mother who then reported the matter to the Police.

He was formally charged with the offence in October last year. Mrs. Smith asked the court to impose a prison sentence of three to four years.

She said the defendant was solely to blame for his actions and that the court had a duty to protect the community, especially children.

Ms Smith also noted the number of sex crime cases brought before the courts in the last two years.

"This hearing comes at a time of great public concern over the sexual abuse of children," she said.

"There has been intense public interest focused in recent years on the law of sexual offences, especially as it relates to the abuse and exploitation of children.

"In the public's eyes, the sentence is the test as to whether justice has been done both to the victim and to the defendant."

But defence lawyer Richard Hector QC asked for a five-year suspended sentence for his client, offering as mitigation the fact that he had no previous record and that he had pleaded guilty and spared the victim from having to take the witness stand.

He said the two had known each other and spent time together for two years before the offence occurred.

"It was not as if he had planned the whole affair, in fact he tried to get (the victim's) mother to stop him from coming to his office. If he had succeeded, this offence would never have occurred. The incident described in the prosecution summary is not of the most serious - trying to kiss the complainant, tickling him all over including his private parts and his buttocks."

He added that the defendant was undergoing treatment and counselling "to help deal with his condition".

And he reminded the court of amendments to the Criminal Code Act which require judges to consider alternatives before imposing a prison sentence.

"This case does not have any of the aggravating features of other similar matters I have come across, such as multiple victims or a history of similar transgressions, and does not in my submission cry out for a sentence of imprisonment," he said.