The man made several threats to police and tried to barricade himself in a property with a woman, police say.
In a statement, police said they were called to a family harm incident on Kingsbridge Place in the suburb of Newlands about 3pm.
Police said once they arrived, they tried to appeal to the man, and after he made threats, police fired multiple shots at him, critically injuring him.
Officers gave him medical attention and requested ambulance support, however the man died a short time later.
A woman at the address was found with non-life threatening injuries and has been treated at the scene by ambulance staff.
A young person at the address was not physically injured, the police statement said.
A formal identification process of the dead man will be undertaken.
Support for the man's family and the people involved would be provided, police said.
"We understand this will be a shock to the Newlands community and we want to reassure them that there is no ongoing risk," said inspector Tracey Thompson, acting Wellington district commander.
"There will be an increased police presence in the area in the coming days as we conduct a scene examination and make enquiries.
"This will also have a huge impact on the officers involved and we will be providing them with support."
The Independent Police Conduct Authority will be notified and a critical incident investigation is underway.
An RNZ reporter at the scene said a resident told him she had heard up to six shots fired in quick succession.
"All I heard was bang, bang, bang, and initially I thought it was a car backfiring but then I saw on social media on our community page that there were reports of shooting a couple of streets away."
Another resident said it was a quiet street where people know each other.
While some gang members lived on the street, they had to live somewhere, he said.
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