The man at the centre of an armed stand-off in the south Auckland suburb of Papakura has died.
Police and forensic investigators are at the scene and will remain there for most of the day.
Three children were released from the house during hours of negotiations with police on Monday.
Police say a shot was fired inside the house at around 1:30pm and they entered to find the man had shot himself.
He was taken to hospital in a critical condition but died several hours later.
Police were called at around 6am by a woman who fled the address, saying she'd been seriously assaulted.
They say they're unsure of what started the confrontation and the investigation is in its early stages.
The children, aged 13, nine and seven, live at the house, as did the man. None of the children were injured.