Crown prosecutor Tanya Smith told the Supreme Court on Friday that Xie was a "trusted relative" who meticulously planned and carried out the killings with an "extreme degree of violence".

Ms Smith said only the imposition of a life sentence for each of the five murders was appropriate

"The killings constitute criminality of the highest order," Ms Smith said.

"The level of culpability is so extreme that it cannot be reflected in a sentence that is less than life imprisonment."

Xie, 53, murdered his brother-in-law Min "Norman" Lin, 45, Mr Lin's wife Yun Li "Lily" Lin, 43, her sister Yun Bin "Irene" Lin, 39, and the Lins' two sons Henry, 12, and Terry, 9 on July 18, 2009.

"He did so in their bedrooms in a very quiet suburban home in the early hours of the morning ... a place were they were all entitled to be safe and secure and a place where young Terry and Henry, only 9 and 12, should have happily pursued their childhood," Ms Smith said.

Xie had given great thought to assembling the murder weapon - a hammer-like object - and used his knowledge of the layout of the house and the front door key, she said.

Xie's lawyer Kara Greiner said she would not present any submissions on his behalf regarding his sentence as he maintains his innocence.

A relative, who cannot be identified for legal reasons, gave a victim impact statement which spoke of nightmares and mental health issues.

"There are not enough words to describe the pain and suffering this has caused me and to those around me," the relative said.

"It has completely changed my life. I do not think that there will be any one aspect of my life that would be the same if this crime had not occurred.

"The pain of losing loved ones never goes away and it does not get easier with time.

"As time goes on others may forget but I will have to live with the aftermath of this crime someone else has committed for the rest of my life."

Justice Elizabeth Fullerton will sentence Xie on Monday.

Senior Crown prosecutor Mark Tedeschi, QC, sat in the public gallery with Mr Lin's parents Yang Fei Lin and Feng Qin Zhu, who wept throughout the hearing.

Xie's wife Kathy Lin sat closest to the dock where her husband sat.

Last month, a jury found Xie guilty of five counts of murder by a majority of 11 to one.

Following the verdict, Xie rose to his feet in the dock and said: "I did not murder the Lin family, I am innocent."

Prosecutors said Xie was motivated to kill his wife's brother and his family because he was enraged by his perceived lowly status within the family.

There was also an alleged illicit sexual motive, the details of which cannot be reported due to non-publication orders.

Ms Smith told Justice Fullerton that, whatever the motive, Xie was "acting in his own self-interest".

The Crown case was that Xie sedated his wife and left her in bed when he went to the Lins' house in North Epping between 2am and 5.30am.

He cut the electricity and used a key to get inside without a sound.

He was carrying a hammer-like weapon - "assembled for maximum effect to incapacitate and kill" - and used it to beat Min and Lily while they slept.

Xie then crept to the second bedroom and killed Irene.

It's likely Terry and Henry woke up and tried to escape before they were murdered, possibly because they had seen Xie and would have been able to identify him.

Outside the court, Kathy Lin said: "He is innocent. We believe that he is innocent. We keep fighting for him."