A Chinese construction worker has been sentenced to 18 years in jail in Australia for murdering his housemate and dumping her body in bushland north of Sydney.

Shuo Dong, 21, pleaded guilty to murdering 28-year-old electrical engineer Qi Yu in June 2018 at the house they shared at Campsie in Sydney's south-west, ABC News reports.

Six weeks later, police found her partially clothed body at the bottom of a gully off the M1 motorway.

Loud wails and angry shouting could be heard coming from the courtroom after the sentence was announced.

The court heard Dong had carried out an internet search two nights before the killing to find out what the sentence was for murder in Australia.

In a victims' impact statement, Yu's parents suggested that Dong had overstayed his visa and killed their daughter to avoid being sent back to China.

They said he preferred to go to prison rather than return to China.

Acting Justice Hidden said he was satisfied the murder was premeditated.

"The offender appears to have acted in a purposeful and clear-headed way in the commission of his offence," he said.

With an automatic 25 percent sentencing discount for pleading guilty, Dong will be eligible for parole in 2031 after serving 13 years and six months in jail.

As the judge finished handing down the sentence, Yu's mother let out a series of loud wails and her father, Zhihe Yu, yelled out in Mandarin: "It's not fair. It's just not fair."

Yu had been communicating with her mother in China on the messaging service WeChat on the night she was killed. She messaged her mother that the lights had gone out in the house.

It was the last her mother heard from her.

Speaking outside via an interpreter, the parents who had traveled from China expressed their dissatisfaction with the sentence.

Yu said the family believed Dong had cynically manipulated the Australian justice system.

"He pleaded guilty to reduce the sentence. He used the law to escape from prison, he doesn't regret what he's done," he said.

The court heard that on the night of the murder, Dong did 18 internet searches on areas of bushland around Sydney.

He later dumped Yu's partially clothed body at the bottom of a gully near Ku-ring-gai railway station.

After his arrest, police used the Google Maps app on his phone to track his movements and find the body.

Acting Justice Peter Hidden said he was not persuaded that Dong was remorseful for his crime.

"In the light of his refusal to disclose how and why he killed Ms Yu, he doesn't demonstrate acceptance of his crime which is an essential aspect of remorse," he said.

The court heard Dong had a difficult childhood in China where he was assaulted at boarding school.

After arriving in Australia on a tourist visa, he worked in the construction industry, where his boss reported he was a quick learner and enjoyed socialising with the other Chinese workers.

During a psychiatric assessment in prison, he revealed he experienced auditory hallucinations and believed that God spoke to him.

The judge said he accepted that Dong was suffering from schizophrenia and was of sub-normal intelligence and that this may have played a role in his "bizarre" crime.

His prospects of rehabilitation, he said, were uncertain.

He said Dong's refusal to give details of how and why he killed Ms Yu had worsened the suffering of her parents.

"Their pain is increased by the offender's failure to reveal the exact circumstances of their daughter's death," he said.

Chinese electrical engineer Qi Yu, 28, was murdered in June 2018 at the house they shared at Campsie in Sydney's south-west in Australia.

Chinese construction worker Shuo Dong, 21, did 18 internet searches on dumping sites before murdering his Chinese housemate.

Qi Yu's parents Qin Ye, centre, and father Zhihe Yu expressed dismay at the sentence.

Chinese worker on tourist visa in Australia jailed for murdering housemate