In jailing Paul Brian Kennedy for at least four-and-a-half years, Judge Robert Toner said that after the teacher's attempted suicide and arrest he broke his bail conditions by downloading child pornography.

Kennedy, 37, was jailed for a maximum of seven-and-a-half years yesterday in Sydney's District Court.

He pleaded guilty to seven offences and admitted another five matters, all of which occurred in 2009 and included grooming children over the internet, producing child pornography and committing an act of indecency.

That last offence involved Kennedy making a 15-year-old boy film him, naked all bar shoes and socks, having simulated intercourse with a plastic vagina in a park in the early hours of the morning.

Judge Toner said the child pornography offences were the "most serious", were "carefully, meticulously and patiently planned" and involved boys aged 12 or 13.

The victims also were unaware Kennedy had placed a web camera directed at the double bed in his bedroom, which also contained a television and DVD player.

The videos he made - one of which ran for eight hours - showed Kennedy leaving the room and then boys coming in separately and masturbating, sometimes with a black vibrator, as they watched pornographic videos.

The judge, describing the offences as "insidious", said the teacher "seduced" them into masturbating and had clearly used his understanding of children gained from years working in the classroom.

In 2008, Kennedy was the subject of disciplinary action after complaints about students attending his house.

The judge said Kennedy made undertakings, including not to have pupils at his house, but a further investigation began after students were reported to be in his car after a sporting event.

One of the grooming offences related to his online chat with an 11-year-old boy who alerted his mother after a photograph of a naked woman appeared on his screen during their conversation.

Kennedy told the boy he could not turn on the webcam as "I am in my spa naked" but later said he could put on his "Borat mankini".

The mother hid in the room when the webcam was turned on and she and her son saw Kennedy naked from the waist up.

Kennedy said: "Hope your mum is not looking".

The boy replied: "No, she is watching TV in the front room".

Kennedy then replied: "She would not be able to control herself, seeing my sexy body".

Police later seized from his home a web camera, the plastic vagina, a Borat mankini, a vibrator and his computer.

That evening Kennedy crashed his car into a guard rail, telling police: "I just accelerated and looked for the nearest object", the judge said.

Judge Toner discounted Kennedy's sentence by 25 per cent for his guilty pleas and noted he was of prior good character.

"That is something of an understatement" he said, referring to testimonies from those who knew Kennedy who were shocked by his conduct, saying it was completely out of character.