The man, who cannot be named for legal reasons, was convicted of 12 child abuse-related charges following a trial in Wollongong District Court last month.

The court heard the man’s conduct ranged from fondling her breasts to digital penetration of her vagina and often occurred in the home he shared with his now-deceased wife.

He also committed acts of indecency in front of her – one involving the masturbation of his pet dog and the other in which he masturbated himself.

The incidents occurred in the mid-2000s when the girl was aged between 8 and 11.

The man’s lawyers had argued during his trial that the accusations were fabricated and had been the product of a daughter – the victim’s mother – who was angry that her father had cut her off financially.

However, Judge Andrew Haesler rejected suggestions the victim had “concocted” her evidence.

In handing down the sentence on Thursday, Judge Haesler said the man’s conduct was not a one-off event.

“The acts form part of a pattern of escalating behaviour by a grandfather towards his granddaughter,” he said.

“They would have been deeply disturbing.”

The victim, now aged in her early 20s, told the court her innocence had been taken away.

“I often think what it would have been like to be a normal little girl who didn’t have to wonder what my pop would do next,” she said.

“I now don’t trust older men … I don’t trust men at all.”

Meantime, another of the man’s granddaughters wrote a letter of support for her grandfather, while his sister described him as “one in a million”.

Judge Haesler set a five year non-parole period. With time served, the man will be eligible for release in 2020.