A baseball bat, golf club and wooden and metal poles have been found at the scene of a violent brawl where a man died at Ingleburn in Sydney's south-west, police have said.

Key points: An 18-year-old-man died in Liverpool Hospital after being treated for severe head injuries sustained in the brawl

An 18-year-old-man died in Liverpool Hospital after being treated for severe head injuries sustained in the brawl Between 50 and 80 people were at a party in Chester Road, Ingleburn when the fight broke out

Between 50 and 80 people were at a party in Chester Road, Ingleburn when the fight broke out Police found baseball bats, a golf club, and metal and wooden poles at the crime scene

Between 50 and 80 people were at a party in Chester Road, Ingleburn, last night when the fight broke out.

People were spilling onto the street as more arrived in cars — some armed with baseball bats.

The man who died was found on the roadway with severe head injuries and could not be revived by ambulance paramedics, Detective Chief Inspector Michael Moroney said.

"This is a very tragic set of circumstances — a young 18-year-old boy who goes out for the evening and who has been killed in such a brutal manner," he said.

"You can understand [his family] would be devastated."

Four men aged 19 were arrested and questioned by police — but two have since been released.

Detective Chief Inspector Moroney has appealed for help from anyone who may have dashcam footage or have taken photos of the fight.

"We're looking for anyone that saw anything, any dashcam footage, or filmed the incident," he said.

"It's important for the sake of the family that they come forward and provide us with information anonymously via Crime Stoppers or calling Campbelltown Police Station."

'A volatile situation'

A large number of police attended the fight, including the Public Order and Riot Squad, the Dog Unit, Police Rescue, Police Transport Command, and officers from other South-West Metropolitan Region Police Area Commands.

"Obviously with 50 to 80 people in the location it was a volatile situation," Detective Chief Inspector Moroney said.

"Police managed to gather the information they needed of anyone who may have witnessed anything, and disperse people."

No-one else was injured and police said there was no connection with a recent stabbing in the area.