Police said the group of friends from Wollongong was driving a 4WD in the Lowes Mount State Forest around midnight when the vehicle left the trail and rolled.

The 15-year-old girl, a passenger in the vehicle, was ejected from the 4WD and died at the scene. Police have yet to formally identify the teenager.

The 24-year-old male driver sustained minor injuries and was taken to Oberon Hospital, where he underwent mandatory blood tests.

Two male passengers also sustained minor injuries.

A 21-year-old man was taken to Bathurst Hospital as a precaution, but did not require further medical treatment.

A third passenger, a 20-year-old man, sustained serious head and abdominal injuries and was airlifted to Orange Hospital. He has undergone surgery this morning.

A crime scene was established and examined by detectives and forensic specialists.

Inquiries into the matter are continuing and a report will be prepared for the information of the Coroner.

Anyone with information that could assist police is urged to contact Bathurst Detectives on (02) 6332 8699 or Crime Stoppers on 1800 333 000.

Police are urging anyone with information about this incident to call Crime Stoppers on 1800 333 000 or use the Crime Stoppers online reporting page at www1.police.nsw.gov.au/.

Information will be treated in the strictest of confidence. Police remind people they should not report crime information via the force's Facebook and Twitter pages.