Police said they received multiple calls after 1am about a man damaging cars, smashing windows in a house and trying to cut power lines in Papatoetoe.
A police officer arrived in the area shortly afterward.
The officer repeatedly asked the man to to put down his weapon, but he continued to advance, police said.
The man was shot and died at the scene, despite being provided with immediate medical assistance.
Police were carrying out a scene examination and speaking with a number of witnesses.
Counties Manukau District Commander Superintendent Jill Rogers said it was a tragic outcome for all involved and police sympathies were with the deceased man's family.
"We will ensure that Victim Support is available to them and will support them through this difficult process."
The man who was shot is still to be formally identified and next-of-kin advised.
Police have launched two investigations into the shooting and also notified the Independent Police Conduct Authority. The matter will also be referred to the Coroner.
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