Detectives from the Serious Crime Squad are investigating the aggravated assault of a 33-year-old man at Humpty Doo overnight.

It is alleged a number of patrons engaged in a fight in the courtyard of the Humpty Doo Tavern at around 8.30 pm.

Early investigations indicate that one patron intervened in an effort to end the fight, and was assaulted. As a result of injuries suffered, the victim was conveyed to Royal Darwin Hospital for treatment where he remains in a critical condition.

A crime scene has been established, and Detectives are eager to speak with anyone who may have information pertaining to the incident.

If you witnessed this incident, or have any information at all regarding this assault please call 131 444 or Crime Stoppers on 1800 333 000.