12/10/2017 1:21 PM AEDT | Updated 12/10/2017 1:21 PM AEDT

Mum Jailed 33 Years For Brutal Murder, Torture Of Three-Year-Old Son Joey

'I had so many thoughts about killing Joey.'

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 spend at least 30 years behind bars after they were 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 in the NSW Supreme Court in Darlinghurst on Thursday.

Joseph had his head slammed in a cupboard, eyes covered with duct tape and naked body shut in a freezing esky in the weeks before he died.

His stepfather, 48, told police he taped a ball into the child's mouth and caused his penis to swell by flicking it with a wooden spoon.

Joseph's 43-year-old mother told police the boy "just pushed my buttons too many times" and she "didn't connect with him".

"I had so many thoughts about killing Joey," she said.

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

Justice Johnson said Joseph was "exceedingly vulnerable" after weeks of abuse by his mother and stepfather, which significantly reduced his capacity to resist the final, fatal assault.

Outside court on Thursday Joseph's uncle said the "appropriate punishment" was "dished out".

"It still doesn't bring back Joseph but there's some closure there in terms of the length of the sentence."

The couple has received "de-facto life sentences", Justice Johnson said, with the stepfather first eligible for parole in 2044 and the mother eligible three years later.