UPDATE: Homicide squad called in after man's body found on Melbourne street

Police have opened a murder investigation after a man was found dead on a narrow suburban street in Melbourne’s south-east overnight.

The body of the man, believed to be in his twenties, was found just after 10pm on Prior Road in Noble Park.

Police initially believed the man was a victim of a hit-and-run, but have since called in the homicide squad.

It's understood the man had suffered serious head injuries.

Investigators set up a crime scene around the road, blocking all traffic between Temple Court and Percy Street.

Forensics have begun collecting evidence.

Witnesses told 9NEWS they heard a commotion just after 10pm, including raised voices and car doors being slammed.

Police are yet to give an explanation as to a grey Audi parked at an angle near where the body was found.

The SES was called in to help light up the dark street overnight.

The man is yet to be formally identified.

Police are calling for anyone with information to phone Crime Stoppers on 1800 333 000. ​