A NSW mother who claimed her toddler died after tripping over a rope tied to the family dogs has been jailed for at least 33 years for his brutal murder.

Her husband will also spend at least 30 years behind bars after the pair was found guilty of murdering three-year-old Joseph after almost two months of abuse at Oberon, near Bathurst, in August 2014.

"This was a terrible crime of child murder," Justice Peter Johnson said when sentencing the pair at the NSW Supreme Court in Darlinghurst on Thursday.

During the trial the jurors heard horrific details about how the boy was treated during the seven weeks he lived with his mother and stepfather in Oberon.

Advertisement

The mother, 42, admitted to police that she had hated her son and thought about pummeling his head with a baseball bat because he reminded her of her ex-husband.
"I had so many thoughts about killing (the boy) because I loved him but I just didn't connect with him," she said.

"Don't get me wrong, I did love that boy ... but there was a part of me that hated him because he looked like his father, because he is his father's child."

Crown prosecutor Margaret Cunneen SC said the couple inflicted "gratuitous violence' on the boy in the lead up to his death, just seven weeks after he went into their care.

"The victim's death must have been terrifying, prolonged and horrific," Ms Cunneen said at the couple's August sentencing hearing.

The jury in their trial heard the boy was aggressively shaken, shut naked and screaming into an esky full of ice, and had his head slammed into a wardrobe door.

The couple admitted to beating Joey with a wooden spoon, taping a ball to his mouth and repeatedly ramming a cupboard door into his head a few days before he died.

Joseph's aunt in August said the way her sister and brother-in-law treated the child was "beyond forgiveness".

The couple clammed their mistreatment did not cause the child's death and that it was instead caused by him tripping over a dog leash during a family visit to the park.

However, prosecutors argued the trip to the park never happened and was just a story the couple made up to explain the boy's death.

Joey was flown to hospital after his mother called triple-0 on August 3,2014 and said her son was not breathing. He had a cardiac arrest and died a few days later.

Joey was found to have died from cardiac arrest and an autopsy also found multiple blunt force trauma injuries on his body.

A jury, which was at times brought to tears during testimony about how the boy was treated, took just two days to convict the couple of murder following a seven-week trial.

During the trial the toddler's older brother told of hearing the little boy screaming after being locked in the esky and also saw him trying to rip duct tape off his eyes, only for it to be stuck back on by the mother and stepfather.