Illawarra man gets 10 years for child sex abuse

An Illawarra man who subjected his two young step-grandchildren to horrific sexual abuse in the 1980s has been jailed for 10 years.

The man, who cannot be named for legal reasons, regularly abused the boy and girl for five years between 1979 and 1984, beginning when the siblings and their mother came to live with him and his wife after the breakdown of the mother's marriage.

The pair were aged just five (the boy) and eight (the girl) when the assaults started.

The siblings and their mother eventually moved out of the home, however the man continued molesting the children whenever they came to visit him, including touching the girl on her genitals and raping the boy.

As the boy grew older he refused to visit his grandparents, resulting in disciplinary action from his parents, who believed he was being disobedient.

Campbelltown District Court heard the boy twice reported the abuse to authorities - once in 1986 to the Department of Community Services, and again in 1990 to the NSW Police - however neither complaint was appropriately followed up and no action was taken.

The boy, now aged in his late 30s, went to police again in 2012. He subsequently met up with his step-grandfather and when he raised the issue of the abuse, the man confessed to his crimes.

The girl also came forward about the abuse she had suffered.

The man was arrested in February last year, and has been behind bars ever since.

On Monday, Judge Rodney Madgwick described the man's actions as "dreadful" and pointed to their considerable impact on the two victims.

"Sexual abuse of children by a family member involves a gross breach of trust and an infliction of a confusing and disorientating experience on the child," he said.

"It's very common for them not to be able to report the abuse to their carers and the sense of disempowerment and loneliness for these two children must have been acute, especially for the boy who was not listened to [for] years when he should have been."

In weighing up the appropriate sentence, Judge Madgwick noted several mitigating factors in the man's favour, including his poor health, advanced age - he will turn 74 on Wednesday - lack of prior offending and his "forthright" attitude with the court in accepting what he had done.

He sentenced the man to 10 years' jail with a non-parole period of six years. With time already served he will be eligible for parole in 2019.