The 12-member panel have spent the past 10 days trying to determine whether or not Sydney businessman Robert Xie is guilty of the murder of five members of his extended family in July 2009, following a marathon nine-month trial in the NSW Supreme Court.

But on Friday they told Justice Elizabeth Fullerton "the jury has reached an impasse and cannot reach a unanimous verdict on the five counts of murder".

Justice Fullerton said she had the power to discharge them if they were unable to reach a verdict but that she would only do so if she was satisfied that there was "no possibility of verdicts being reached".

"It is the experience of our criminal justice system that juries can often reach agreement if given more time to consider and discuss the issues," Justice Fullerton said.

"Even in this trial where you have been in consistent and focused deliberation for 10 days, I would still need to be satisfied that there is no prospect of a verdict.

"Calm and objective discussion may enable you to reach a point of satisfaction that your original position was wrong and that the position of your fellow jurors is right.

"I direct you to retire again and see if you can reach a unanimous verdict in this trial."

Mr Xie, 51, is accused of murdering his brother-in-law, Min "Norman" Lin, Min's wife Lily, his two sons Henry, 11, and Terry, 9, and Lily's aunt Irene, in their North Epping home.

He has pleaded not guilty.

The prosecution alleges that Mr Xie was driven by a combination of bitter resentment over what he saw as the Lins' favoured status within the broader family group, and a desire to get his hands on his brother-in-law's financial assets.

It says the former restaurant owner allegedly crept into their house using the key he and his wife had been given, and then beat the Lins to death with a hammer-like object in their bedrooms.

Mr Xie's wife, Kathy Lin, gave sworn evidence during the trial that her husband was with her in bed on the night in question and did not leave their bed, effectively providing him with an alibi.

But the Crown accused Mrs Lin of concocting her evidence, with Crown prosecutor Mark Tedeschi, QC, declaring that she was "an abject liar", who was "willing to say or do anything to protect her husband".

This was part of a large, complex, circumstantial case assembled by the Crown.

It included evidence that Mr Xie was one of just a few people who had a key to the Lins' home and who could have negotiated his way around their house in the dark.

"Anybody who enters the house [with a key] shows an incredible degree of arrogance and self-assuredness, and a completely unrealistic belief that they are immune to detection," Mr Tedeschi told the jury.

He also said that a series of bloody shoe prints found in the house came from the kind of Asics trainers that Mr Xie preferred and that they were within a range of sizes that included the accused.

Months later, when news of this evidence allegedly reached Mr Xie after his wife was informed by police, he was allegedly recorded on a camera hidden by police in his home cutting up shoe boxes and flushing them down the toilet.

Prosecutors also allege that a small smudge of blood that had been transferred from the crime scene was found in the garage floor of the home owned by Mr Xie and his wife.

Three separate sets of DNA testing found a mix of up to five different DNA profiles, and the trial heard that there was a far greater likelihood that the profiles belonged to the murder victims than any other single member of the Asian community.

The defence countered that, not only was the Crown unable to prove conclusively that the DNA belonged to all victims from the Lin family, but could not even prove conclusively that it was blood.

Mr Xie's barrister, Graham Turnbull, SC, argued from day one that it was impossible for one man, particularly a man of his client's age and small stature, to have committed the alleged murders in the way the Crown claimed had happened.

He said that, far from being angry or resentful toward the Lins, Mr Xie had a close and loving relationship with them.