A manhunt is underway after a man died following an alleged assault in northern NSW.

The man was found lying unconscious on the side of William Street in Tweed Heads South by a local resident about 3.15am on Sunday.

Authorities rushed to the scene and treated the man, aged in his 30s, for serious injuries however sadly he could not be saved.

He is yet to be formally identified, with police establishing a crime scene as the investigation into the incident continues.

The State Crime Command’s Homicide Squad has been called in to assist with the investigation.

Police are urging anyone with information into the incident to contact Tweed Heads Police or Crime Stoppers on 1800 333 000.

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