A New South Wales man who violently bashed his former girlfriend to death and left her body in a bathtub has been jailed for almost 20 years. 

Rodney Dempsey attacked 27-year-old Jenoa Sutton with a hammer-like object and piece of wood, before leaving her body in the bathtub of her Lithgow home on March 8, 2012. 

He body was found by her sister Erica Ellery, who went to check on Ms Sutton when she didn't pick her two children up from school. 

In sentencing Dempsey to 19-years-and-nine-months jail, with a non-parole period of 14-and-a-half years, Justice Peter Hamill said it was "criminality of an extremely high order".

He said Dempsey, 53, was possessive of his former partner, and, after they broke up, they argued about custody and money. 

The NSW Supreme Court heard Dempsey became angry when Ms Sutton wanted to move from Lithgow to Dubbo with the children. 

The morning of the attack he drove to her house and assaulted her repeatedly, fracturing her skull and inflicting multiple abrasions to her head, neck, legs, and pelvis. 

"This was a brutal and sustained assault that continued for some time and culminated in a ferocious blow to the head," Justice Hamill said.

"It was not premeditated, but it was the manifestation of his possessive behaviour."

After the attack, Dempsey got takeaway from Mcdonald's then returned to his job as a mechanic. 

He also took the victim's mobile phone, which has never been recovered. 

After a long-running police investigation, he was arrested and charged in 2020. 

Justice Hamill told the court he discounted the jail sentence by 10 per cent because of a guilty plea before the matter got to trial. 

The court heard Dempsey was adopted as a child, and he alleged his adoptive mother beat him and locked him up. 

He also alleged he was sexually abused as a child by a Catholic Priest. 

Justice Hamill said Dempsey had a record of drug use and had previously been convicted of offences including theft in Western Australia. 

"It cannot be said he is a person of prior good character," he said.

The judge said Dempsey must be held accountable for his actions and domestic violence cannot be tolerated by the courts. 

He expressed his condolences to Ms Sutton's family. 

"No sentence I impose will be enough for them, given the loss they've suffered."