Police believe they have found the body of Chinese woman Qi Yu, who disappeared last month.
The body was found at the side of the M1 motorway in bushland, about one kilometre from the exit at Mount Kuring-gai about 8.30am.
Ms Yu, 28, was last seen by friends at her Campsie share house in the city's southwest on the evening of June 8.
Her 19-year-old housemate was charged with her murder days later and remains in custody.
"While the body has yet to be formally identified, detectives from Campsie Police Area Command investigating the disappearance and alleged murder of 28-year-old Campsie woman, Qi Yu, are on scene to conduct inquiries," a NSW Police Force spokesperson said.
A crime scene has been established and police are advising motorists to avoid the area.
Police search teams, supported by cadaver dogs, helicopters and marine units, have spent weeks scouring vast tracts of bushland and waterways around the area for signs of her body.
Phone records suggest Ms Yu's white Toyota Corolla travelled north to the area around Mount Kuring-gai, Berowra and Cowan and then back to Campsie between 8.30pm and midnight on the night she disappeared.
Chinese national Qi Yu vanished last month. Source: AAP
Her 2016 model hatchback was later found dumped at Burwood in Sydney's west the same weekend she disappeared.
Ms Yu's parents - who flew out from China in the days after she went missing - have been distributing flyers at Sydney train stations which read: "Looking for Missing Girl Qi Yu" as they struggled to come to terms with their daughter's suspected murder.
The local Berowa community also held a candlelight vigil and public prayer for the 28-year-old at the end of June to show support for Ms Yu's family and the searchers.
Berowra Heights local Kate Glenn said the search activity had been distressing.
"Explaining this to our children - why there are horses, dogs and choppers, SES everywhere for the past few weeks is very confronting," she previously told AAP.
