23/06/2016 6:03 PM AEST | Updated 15/07/2016 12:54 PM AEST

Farmer Ian Turnbull Sentenced To 35 Years For Moree Murder

The Judge handed down the sentence with a non-parole period of 24 years.

James Alcock/Fairfax
81-year-old farmer Ian Turnbull has been sentenced to a maximum of 35 years in jail for a violent murder in 2014.

The son of an 81-year-old farmer who chased down and shot a New South Wales environmental officer over a land dispute in 2014 has blamed land clearing laws for the officer's death.

Ian Turnbull, who was 79 years old at the time of the attack, was sentenced to a maximum of 35 years in jail on Thursday.

He was found guilty in May of the murder of Glen Turner using a hunting rifle near Moree in north-western New South Wales. In sentencing him, Justice Peter Johnson told a full courtroom in the NSW Supreme Court that he believed Turnbull intended to kill Turner, and handed down a non-parole period of 24 years.

"I have taken into account that this sentence will almost certainly constitute a de facto life sentence with the offender dying in custody before the expiration of the non-parole period," Justice Johnson said, according to the ABC.

The judge also dismissed the argument that Turnbull had shown genuine remorse for committing the murder and also for holding Turner's colleague Robert Strange at gunpoint for more than 20 minutes.

"The events ... involved the offender prolonging the process of murdering Mr Turner, thereby heightening the terror to which Mr Turner was subjected, before the final and fatal show was fired," he said.

Environmental officer Glen Turner was violently murdered in 2014, a court has heard.

The sentence comes after a five-week trial in May where Turnbull pleaded not guilty to murder but guilty to manslaughter on the grounds of substantial impairment due to mental illness, according to the Sydney Morning Herald.

The jury heard Turnbull was facing prosecutions by the Office of Environment and Heritage in the Land and Environment court for illegal land clearing, which he continued to do after being told to stop, to increase land value and productivity.

The incident occurred following years of tension where Turnbull believed he was being singled out by authorities for his actions, before driving out in search of Turner in the Croppa Creek area near Moree and shooting him in the neck.

The court heard Turnbull then chased Turner for 22 minutes before firing the fatal shot into his back despite Strange pleading with him to put the gun down.

The families of both Turnbull and Turner watched as the sentence was handed down and spoke outside the court following proceedings.

Peter Rae/Fairfax Media
Glen Turners partner, Alison McKenzie with Turner's sister, Fran Pearce leaving the court

Grant Turnbull, the son of Ian Turnbull, blamed State Government native vegetation laws for the death, saying if the Vegetation Act is not changed, similar acts of violence could occur again in the future.

"The frustration that's out there, it's not just my father, it's many people out in rural New South Wales that are extremely frustrated, extremely frustrated with the way it's administered and the act itself, it just needs to change," he said.

"It just shouldn't happen to two more families. The politicians need to listen. They need to listen to the people."

Ian Turnbull showed no emotion as the sentence was read out, only nodding once and waving towards his wife, Robeena, who was seated in the front row of the court.

Alison McKenzie, Turner's wife, said: "It's the end of a long road for us; it'll never bring Glen back so no matter what sentence was given, it's never going to change what happened and I'm just glad justice has prevailed.

"I've grown used to Glen not being around but the circumstances in which it happened, I will never ever be able to accept."