A carload of youths brandishing knives and machetes were seen arriving in central Hamilton before a fight between two groups turned deadly.

Police say a 20-year-old man died in hospital - and three others were in injured - after an altercation near the intersection of Hood St and Alexandra St around midnight.

Police are treating the man’s death as a homicide and describe the incident as a “senseless act of violence”.

A source told the Herald that “a carload of youths” were seen arriving near the scene brandishing knives and machetes.

The area today remains cordoned off to the public while police investigate - including looking for “the implements involved”.

The source did not believe the incident was gang related.

Hato Hone St John told the Herald three people were transported to Waikato Hospital and one was treated at the scene for minor injuries.

Police were alerted to the altercation about 12.10am and responded immediately.

Detective Sergeant Reece Durston, Area Manager Investigations, said police are seeking those responsible for the “senseless act of violence”.

“Some of those involved, including the offender, left the scene immediately after the incident. The investigation team is moving at speed to locate them and the implements involved.

Police had Alexandra St cordoned off this morning. Photo / Victor Waters, RNZ

“The investigation team is working hard to understand how and why this happened, and we are wrapping support around the family of the deceased, and the other victims,” said Detective Sergeant Durston.

A visible police presence will remain in Hamilton as inquiries continue, and Police will be carrying out “reassurance patrols” in the community.

“There is a large scene to work through and we ask that the public avoid the area and thank them for their understanding,” Durston said.

The cordon includes a car park, and anyone with a vehicle parked there is asked to make a report online, or by calling 105. Please use the reference number 250720/3051.