Workmen spotted the car in bushland off Elizabeth Drive in Cecil Park about 11.40am on Monday. Inside the white Hyundai i20 was the body of an 18-year-old woman.

Police now believe the woman, from Oxley Park, was driving the vehicle east along Elizabeth Drive about 4.30am on Sunday when the vehicle hit a power pole and tree, before crashing down an embankment. The vehicle came to rest about 10 metres from Elizabeth Drive, between Duff and Cecil roads.

The woman, who was believed to be the only person in the vehicle, died at the scene.

Detective Inspector Brendan Bernie, from the Green Valley local area command, said the wreckage was not clearly visible from the road. The workmen discovered the vehicle more than 30 hours after the estimated time of the crash.

Investigators were able to narrow down the time the crash because a power outage was reported in the area at 4.30am on Sunday.

"There was a power pole and tree just further west of where the vehicle was found which had damage consistent with being hit by a car," Detective Inspector Bernie said.

"The business that operates the poles has recorded an outage at that time of the morning, which suggests the collision may have occurred about 4.30am.

"Unfortunately the car went into some quite thick scrub and down an embankment. It wasn't until workmen doing some work in the area on Monday morning came across the vehicle that police were alerted."

Detective Inspector Bernie said the woman's family was extremely upset, and did not know what she was doing out at that time of the morning.

"Like the police, they are seeking answers to what has happened," he said.

Detective Inspector Bernie said there were no known witnesses to the crash, and police were appealing for anyone with information about the woman's movements on Saturday night or the early hours of Sunday morning to contact police.

Anyone with information has been urged to contact Crime Stoppers on 1800 333 000 or use the Crime Stoppers online reporting page.

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