A 32-year-old man has been charged with murder after the body of a teenage boy was found in bushland near Sydney’s southwest.

A witness discovered the 15-year-old’s body by a roadside at Wilton around 7.25am on Saturday.

Detectives will allege the man stabbed the teen during a physical altercation.

Police said the 32-year-old man had presented himself at Narellan Police Station shortly after 4pm after a public appeal for information.

He was arrested and on Sunday morning police revealed he had been charged with murder and was refused bail to appear in Parramatta Bail Court.

Camden Police believe roughly a dozen young campers might have gathered on Friday evening near the area.

“Information that we have at this stage is that there may have been a group that were camping in that area, and we believe that persons associated with that camping event may have been involved,” Acting superintendent Tim Calman told the media on Saturday.

“We believe something has happened on the Friday evening, but the exact time in relation to what has actually happened is still under investigation.”

While the deceased was yet to be formally identified, police believed him to be a 15-year-old boy from the Wilton area.

His family had been notified, Calman said, and were being supported by police after the “tragic” incident.

“We put our thoughts out to the family,” he said.

“The family and the wider circle of friends will be doing it tough on Saturday afternoon as they go through this process.

“Police will continue to support them as we try to get to the bottom of actually what’s happened.”

Police are appealing for anyone with knowledge of the incident or dashcam or mobile footage to come forward, as well as anyone who might have been in the area since 6pm on Friday.

-with AAP