"An ambulance arrived very soon after ... they located a man who was injured and despite their best efforts they were unable to revive that person, so we've got one person deceased."
The incident happened just after 11pm on William Bolfield St, close to Sandringham Rd, Mt Roskill.
Watson said another man who was suffering from serious injuries had travelled to a house nearby.
He had been transported to hospital and was being treated for his injuries.
A number of people were assisting police with their inquiries, Watson said.
"We're seeking any members of the public that might have information, or know what occurred here tonight, to contact us as soon as possible."
No one was in custody.
Detective Senior Sergeant Glenn Baldwin would be leading the investigation today.
The fight happened at an address on William Bolfield St, in the Auckland suburb of Mt Roskill. Image / Google Maps
The crime scene at William Bolfield St the following day: December 12, 2018.
Sharyn Allan lives directly accross the road from the property in which the fighting filtered out from, but says she barley heard the commotion from the back of her house.
"I woke up this morning and my house was covered in police tape and there was an ugly big pool of blood on my driveway," Allan said today.
"So I've been a bit upset all day, thinking I didn't get out of bed. Not that I could have done anything."