Powerful gusts reaching speeds of up to 155km/h (96mph) have caused nearly 90,000 properties without power and forced agencies to call off more than 100 air travel services, based on domestic outlets.
These gusts are impacting the whole South Island and southern parts of the North Island, according to the weather forecasting body.
The nation's agencies have announced infrequent red wind warnings - the top caution category - in core zones including these major districts.
Locals have been advised to avoid going outside, avoid travel, and prepare for more utility disruptions.
Broad Impact and Crisis Response
The electricity loss appears to be affecting households predominantly in the South Island, while agencies report that the electricity supply was being restored progressively.
Local media have indicated that in some places homes have lost their roofs, whereas trees and electricity poles have been knocked down by the winds.
Within the capital, a person was fatally injured after being hit by a wooden fragment at a popular trail walking spot on Tuesday.
Also in the capital, a individual was blown onto moving cars on a thoroughfare by a strong gust of wind, in a moment that was captured in a widely shared car camera footage.
Aircraft services to and from the urban area have been halted due to the gusts, and various routes and public facilities are not operating.
At the same time local leaders have issued a crisis declaration, to facilitate disaster response efforts.
Strike Action Alongside Extreme Weather
The wild winds on today come as many of teachers, doctors and other public workers are participating in what has been called a "major walkout", requesting better pay and working conditions.
Yet the extreme weather has forced them to alter some of their plans, with various open-air gatherings relocated inside or called off.
Similar gusts are impacting the nearby nation, causing a high-temperature event to the remote areas.
Agencies have announced fire bans for concern about bushfires.
