Hunt two people after the man was found dead in the middle of Sydney street

Forensic police officers at the scene where a body was discovered in Minogue Crescent in Forest Lodge, Sydney.

Two people are fleeing after a man suffered serious head injuries in an "altercation" before staggering onto a suburban Sydney street and collapsing dead.

Detectives say a gun was discovered near the man's body in Forest Lodge on Friday afternoon, but they have not yet confirmed that he was shot.

It has been speculated that a samurai sword could also have been used in the attack.

A body is seen in Minogue Crescent in Forest Lodge, Sydney.

AAP

"A firearm was found on the scene, but at this time we are not sure if that was the cause of the injuries," interim superintendent Sam Crisafulli told reporters.

"I'm not in a position to talk about exactly what weapons were involved."

The victim, in his last 20 or 30 years, died after an "altercation" with another man and a woman, he said.

A nearby house has been declared a crime scene as was the intersection of Hereford Street and Minogue Crescent where the body of the victim was found around 1pm.

"We believe that the injuries were caused during the altercation and that he was able to go down to the street where his body was found," Supt Crisafulli said.

Witnesses told police they saw the victim bleeding profusely from his head as he staggered on nearby Ross Street, he said.

"I am satisfied after a search in the area by the police, the people we are looking for are not here at the moment," he said after 3 p.m., adding that local residents could soon return to their homes.

Philippe, who has lived in the area for more than seven years, said it was generally a very quiet neighborhood.

"When I saw the helicopter, I thought it was a blow and a race," he told AAP.

There was a stabbing close a few weeks ago, Philippe added, but the violence was rare.

Anyone with information should contact Crime Stoppers at 1800 333 000.