The elder brother, 14, known as CT, was first abused when he did a week of work experience with Souter, a qualified carpenter. As CT climbed a ladder Souter followed him up, slipping his hand up the boy's shorts and rubbing his penis before climbing down and ejaculating himself.

Later when CT helped him at a carpentry job, Souter rubbed himself against the boy simulating sex and told him to think about the woman who owned the house. He then masturbated CT after telling him to put on the woman's stockings. CT's younger brother, NT was about 10 years old when he first met Souter who would visit their home for dinner and family barbecues and go to the beach with them. Four years later, while NT helped Souter to build a new church hall, Souter asked him, "Do you want me to show you how to become a man?" before making the boy perform sex acts.

Later, while taking the boy on a bike ride Souter said to the boy: "Let's go to the sand hills. I can show you how to make babies." He held his hand to the boy's mouth while having anal sex with him. NT told health workers about the abuse after he experienced an anxiety attack while on a church convention in Alice Springs.

Souter was expelled from the congregation before being readmitted after he apologised to church elders. Souter abused the the third boy, who worked for him, several times including while the boy slept as they drove home from a job. Souter sat with his head down throughout the sentencing while his three victims, now adults, and their family and friends sat in the back of the court.

He is serving a prison sentence for the sexual assault of another brother of CT and NT, the court heard. Judge David Freeman said the facts of this case were "distressingly similar to the case for which he is already serving time".

"That he has debauched all three sons of the one family has done extreme damage," Judge Freeman said. "The guilt of the parents for allowing a fellow member of their church to defile their sons is palpable." Souter will serve a maximum of 10 years and six months in prison with a non-parole period of seven years and nine months. He will be eligible for parole in 2015.

Outside court the victims said they were relieved by the sentence and that they could now begin to move on with their lives.