Dozens of schools across the country have been closed and power outages are reported throughout thousands of homes.
A state of emergency has been declared in seven provinces including Taranaki, Nelson Tasman, Westland and Christchurch.
Air New Zealand grounded all flights from Wellington from 2.45pm (0145 GMT) as weather authorities issued warnings of severe weather and heavy rain and gusts of up to 93 miles per hour.
"The full impact of the storm will be felt overnight and tomorrow morning", said Christchurch Mayor Lianne Dalziel. "We are expecting homes to be flooded". The cyclone also hit Fiji, Samoa and American Samoa.
The petition to undo latest Snapchat update hits a million signatures
So, it's not surprising that when it appeared to begin backtracking on its latest update to individual users, folks got excited. The outage comes amid an uproar over a redesigned iOS app, which has users looking for ways to install the previous version .
However, the storm has downgraded significantly, though residents have been told to brace for floods and winds of up to 150km/h.
Air New Zealand has cancelled numerous outgoing flights due to the threat posed by ex-cyclone Gita.
"Even though the deep low pressure system moves away from us early on Wednesday, the effects of Gita will last a few more days, with further rain likely about central New Zealand until Thursday", said Lisa Murray at MetService in Wellington.
New Zealand Prime Minister Jacinda Ardern said: "My message, still, to people is please look out for your local warnings and expect disruption to travel and please just be careful".
- Website tracking 'Starman,' Elon Musk's Tesla on road to Mars
- Google is Offering "Loyal Nexus Owners" 20% Off the Pixel 2/2XL
- Luis Enrique Would Be A Success At Chelsea- Andres Iniesta
- Mental health, safe schools are Trump priorities
- We gave PSG confidence before Madrid clash - Dijon respond to Rabiot jibe
- Samsung Squeezes 30TB Into a 2.5-Inch SSD
- India, Iran agree to eliminate 'forces that support terror'
- Potential Barcelona lineup against Eibar
- Five killed in attack on church in Russia's Dagestan
- José Mourinho Needs To Spend More Time Coaching Attacking Plays