Intense gusts hitting speeds of up to 155km/h (96mph) have caused around 90,000 properties without power and led authorities to cancel more than 100 flights, based on domestic outlets.
The gales are impacting the complete South Island and southern parts of the northern region, according to the weather forecasting body.
Officials in New Zealand have announced infrequent severe gust advisories - the highest alert level - in core zones including Canterbury and Wellington.
People have been urged to avoid going outside, stay off roads, and get ready for more utility disruptions.
Widespread Impact and Crisis Response
This outage seems to be impacting residences mainly in the South Island, while officials state that the electricity supply was being slowly brought back.
Domestic outlets have stated that in some places homes have lost their roofs, while trees and electricity poles have been knocked down by the gusts.
Within the capital, a man was killed after being hit by a tree branch at a frequent walking route on Tuesday.
Meanwhile in Wellington, a female was blown onto oncoming traffic on a street by a strong gust of wind, in a incident that was filmed in a widely shared car camera footage.
Flights to and from the city have been halted as a result of the winds, while certain highways and community centers are not operating.
Meanwhile local leaders have announced a crisis declaration, to facilitate disaster response efforts.
Work Stoppages Alongside Extreme Weather
The powerful gales on Thursday coincide with numerous of school staff, physicians and civil servants are participating in what has been termed a "significant labor action", requesting better pay and working conditions.
Yet the extreme weather has pressured them to modify some of their plans, with various open-air gatherings relocated inside or abandoned.
Similar gusts are also sweeping Australia, ushering in a high-temperature event to the country's outback.
Agencies have announced burning restrictions for fear of wildfires.
