Police say a man who called them to a central Auckland apartment where a woman was found dead is likely to remain in hospital for several days.
Police are carrying out a homicide investigation.
The man, thought to be in his early 20s, suffered a serious injury to his hand and was taken to Auckland Hospital for medical attention. He is being kept under police guard.
Ambulance staff were called to the apartments on Winchester Street in Newton shortly before 4pm on Tuesday and in turn notified police.
A post-mortem is due to be held on Wednesday on the body of the 30-year-old woman, who the ambulance service says was stabbed.
The body was removed from the apartments on Tuesday night, and forensic scientists, police photographers, and a pathologist were at the scene.
Police have not released an official cause of death.