Police have launched a homicide investigation following the death of a man at Auckland City Hospital.

The man had suffered injuries in an incident in Orchard Rise, Rosehill, on May 15.

He was one of two people hospitalised as a result of what police described as a disorder incident.

Another person was taken to Middlemore Hospital in a serious condition at the time but has since been discharged.

"Sadly, the man taken to Auckland City Hospital died on Wednesday after remaining in a critical condition since the incident occurred," Detective Senior Sergeant Mike Hayward said today.

"Police are unable to release details of the man at this stage while there are still family members being advised.

"Police would like to reassure the community that this is believed to be an isolated incident, with both parties involved in the disorder being known to each other."

A 24-year-old man has been charged over the initial disorder incident and will be appearing in the Papakura District Court at a later date.

Police could not rule out the possibility of further charges being laid. Inquiries into the incident were continuing.

The Herald reported at the time that one man has been seriously hurt and a second was critical following an early morning fight.

A police spokeswoman said two people had been "seriously assaulted" in an altercation between two groups just before 2am.

Orchard Rise was closed while the scene was examined by investigators.

A St John spokesperson said the ambulance service was notified of the incident at 1.58am and sent two ambulances, one rapid response vehicle and one managing vehicle to the property.

"We assessed and treated two patients; one in a critical condition who was transported to Auckland Hospital and one in a serious condition who was transported to Middlemore Hospital."