In a hearing in the NSW Supreme Court today, a statement by Greg Simms was read out describing how the loss of his sister had impacted generations.

"We considered you an equal in all respects. We trusted you. You repaid us by committing the ultimate betrayal," Simms wrote.

"It was a brazen act of a conniving monster hell bent on one thing, getting what you wanted at any cost," Simms said.

Wearing prison greens sitting in the court dock, Dawson listened to statements from Simms as well as Lynette's sister Patricia Jenkins and his own daughter Shanelle Dawson.

Before reading her statement, Shanelle took a pause to fiercely stare at Dawson from across the courtroom, breaking into tears before speaking.

"The night you removed our mother from our lives was the night you destroyed our sense of safety and belonging in this world," she said.

Saying she had glimpses of memories from the "nightmare night" her mother disappeared, she said her life had been shattered, she found it difficult to trust men, and she had been diagnosed with PTSD after learning what her father was capable of.

"The torture of not knowing what happened, of what you did with her body - please tell us where she is. I hope you will finally admit the truth to yourself," she said.

In a five-hour judgment delivered on August 30, the judge outlined why Dawson was guilty of killing his wife and disposing of her body.

Dawson went missing from the couple's Bayview home in Sydney's northern beaches. Her body has never been found despite extensive police searches.

Dawson has consistently denied any involvement in his wife's disappearance, claiming she simply up and left her family home and children without a trace.

Justice Harrison rejected this version of events as "ludicrous".

Two days after the judgment, a lawyer for the ex-Newtown Jets rugby league player told the court his client had already received death threats while at Silverwater prison due to the high-profile nature of the case.

The case shot into the public eye largely as a result of The Teacher's Pet podcast by The Australian's Hedley Thomas which garnered millions of views across the globe.

On the day of the guilty verdict, police confirmed the investigation into Dawson's murder was not over and urged anyone with information to come forward.