Gabrielle was downgraded from a category two to a category one storm before it made landfall but is still forecast to bring severe weather.
The regions of Northland and Auckland are currently under a state of emergency.
Parts of the North Island were badly damaged by flooding only weeks ago.
Northland declared a state of emergency then too over fears of unprecedented rain, but those concerns proved to be unfounded.
This time, however, gale force winds and heavy rain have been reported, leaving as many as 22,000 people at a time without power in the region, according to local media.
Some residents have been warned that it may take days for power to be restored.
Far North mayor Moko Tepani told Television New Zealand that he thought the roof of his house was going to blow off because the wind was so strong.
People who knew their homes were flood-prone were advised to evacuate ahead of the storm's arrival.
Declaring a state of emergency gives local authorities greater power to respond to dangerous situations and allows them to restrict travel and provide aid.