Northern Territory Police are investigating the death of a man at a home in Darwin River overnight.

Police and emergency services responded to a report of a unresponsive man at a home just after 10:30pm.

Paramedics conducted CPR on the man, however he died at the scene.

Investigations indicate the man had been involved in a physical altercation with another person known to him, prior to his death.

The area has been declared a crime scene and police are treating the death of the 53-year-old man as suspicious. A 54-year-old man is assisting police with their inquiries.