A 27-year-old man has been arrested for aggravated assault after allegedly pushing a 47-year-old man off a balcony during a fight at a northern suburbs apartment block on Saturday afternoon, NT Police said.

Shortly before 5 pm, witnesses reported to police that they saw two men known to each other involved in an altercation with one of the men allegedly pushing the other from the second-storey unit’s balcony and fleeing the scene.

The 47-year-old man was rushed to Royal Darwin Hospital and underwent surgery with a number of broken bones, police said.

Witnesses said the younger man was wielding a knife at some point during the altercation.

Detective Senior Sergeant Karl Day police are investigating whether the older man fell or was thrown.

“The 27-year-old returned to the location at 8:30 pm, where he was arrested by police, and will be charged with serious harm,” Sr Sergeant Day said.

Police are urging anyone who witnessed the incident, or who has information, to make contact at 131 444, quoting reference number 10185827. You can also contact Crime Stoppers at 1800 333 000.