A homicide investigation is under way after the man was shot dead in the Glass Rd, Mt Roskill, house about 9.30pm on Thursday, Detective Inspector Scott Beard said.
"Two armed offenders have entered the address and an altercation has taken place with the occupants inside the house.
"One of the occupants, a man in his 20s, received a gunshot wound and has died at the scene."
Two other people had received non-life-threatening injuries and were taken to hospital.
The offenders had fled and had yet to be located.
A scene guard has been in place overnight and police will be carrying out a scene investigation today.
Armed officers are at the scene this morning. About 50 metres of the suburban street has been cordoned off.
The property where the incident occurred is owned by Kainga Ora, formerly Housing New Zealand.
Last night a witness told the Herald that one person had died while as many as three others were injured.
