Judge mulling jail time for Chris Dawson

A NSW judge is now considering how long Chris Dawson will spend in jail for murdering his wife Lynette in 1982.

After a sentence hearing in the NSW Supreme Court on Thursday, Dawson's lawyer Greg Walsh said the former schoolteacher would spend his final years behind bars if an appeal against his conviction failed.

"Unless he's successful in his appeal, he'll die in jail," he told reporters outside court.

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Earlier, Justice Ian Harrison heard arguments about how long Dawson, now 74, should spend behind bars for killing his wife and disposing of her body four decades ago so he could have an unfettered relationship with a high school student he was obsessed over, referred to as JC.

Crown prosecutors are pushing for a higher sentence for the deliberate act of murder and domestic violence, pointing the judge to other murder cases of "very great heinousness".

On the other hand, Dawson's lawyers have argued his jail term should be lessened because of factors such as the "hysteria" created by high levels of media publicity regarding the case.

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Mr Walsh told the court the former rugby league player was also showing signs of a brain condition called chronic traumatic encephalopathy.

His condition had deteriorated significantly, having spent 10 weeks in custody after Justice Harrison's guilty verdict in August, and was experiencing memory loss and slurring of his words, Mr Walsh said.

On Thursday, three powerful victim impact statements were read out to the court from Mrs Dawson's siblings Greg Simms and Patricia Jenkins and her daughter Shanelle Dawson who was four years old at the time of the murder.

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Shanelle wrote that her father had ripped her mother away from her, depriving her of maternal cuddles, a mum's love and a role model for her own mothering.

"You took that away and so much more and you had no right to. You are not God," she said during an emotional reading of her statement on Thursday.

"It hurts me deeply to think of you in jail for the rest of your life. But I also choose not to carry your burdens anymore. I need my life back."

Dawson received a number of testimonials to his good character which the judge will now consider, including statements from his two other daughters and his brother Peter Dawson.