SYDNEY • A former surgeon who bludgeoned to death five relatives with a "hammer-like object" in one of Australia's most ferocious killings was jailed for life yesterday.

China-born ear, nose and throat specialist Robert Xie, 58, clubbed two children and three adults around the head and face as they lay sleeping in their home in 2009, hitting one of them 18 times.

Xie, who emigrated from China 15 years ago, was told he would die in jail for the murders of his brother-in-law Norman Lin and his wife Lily, their children Henry and Terry, and Lily's sister Irene Lin.

Justice Elizabeth Fullerton told a Sydney court that Xie's horrific slaying of the five - including one as young as nine years old - showed "resolve... to persist with the infliction of extreme violence".

It was a "single episode of brutal and calculated murderous violence (and) a course of offending that can only be described as heinous in the extreme", Justice Fullerton was quoted as saying yesterday in an Agence France-Presse report.

"There was a discernable pattern in the shape and contour of many of the blunt force injuries on the heads and faces of the victims."

Prosecutors said Xie, who had a key to the family home, was motivated by bitterness linked to his lowly standing with the family. There was also an alleged illicit sexual motive, the details of which cannot be reported owing to statutory non-publication orders, according to The Sydney Morning Herald.

After four trials - two were aborted and a third hung - Xie was found guilty by a majority 11 to one last month.

Xie and his wife Kathy Lin - Norman's sister - alerted the police to the bodies, leading to a huge investigation spanning Australia and China. He was charged in 2011.

Xie, who was given five life sentences without the possibility of parole, maintains his innocence, and is supported by his wife.

"He is a loving and caring family man," Ms Lin said, adding: "He was wrongly charged with a crime he did not commit. He is a scapegoat."

"We need people to support us to correct this miscarriage of justice... to bring him home," she said, adding that Xie would appeal.

In passing sentence, the judge said she was satisfied that Xie remained a danger to the community.

She also said life imprisonment was the only appropriate sentence because of the "far reaching and immeasurable harm done to Miss AB and the community at large".

Miss AB is a relative of the Lin family. She cannot be identified for legal reasons, said The Sydney Morning Herald.