Auckland residents have been warned to cancel their Easter plans in order to stay safe.
Flights across the country have been delayed or cancelled, with Air New Zealand suspending its operations from Tauranga Airport on the North Island.
Airlines have warned passengers to expect disruptions to normal flight schedules in and out of the country.
The monster storm is expected to hit land tonight local time and move to the South Island early Friday morning.
Cyclone Cook has already killed one person when it tore through New Caledonia earlier this week.
The Foreign and Commonwealth Office (FCO) has updated its travel advice for Brits heading to New Zealand.
On its website, the FCO warned: “A State of Local Emergency has been declared in the Bay of Plenty Region (east coast, North Island).
“Following severe flooding earlier in the week beginning April 10 2017, further very heavy rain and high winds are forecast until Saturday April 15 2017 for much of New Zealand.
“The MetService is predicting major impacts for Coromandel/Western Bay of Plenty. Check local weather forecasts and take the advice of local authorities.”
It’s been a difficult time or the Bay of Plenty region, which was battered by the effects of Cyclone Debbie just last week.
Despite the current flight cancellations and severe weather, New Zealand is typically a safe destination for British travellers.
It has a low threat of terrorism, and according to the FCO, most of the 200,000 UK visits each year are trouble-free.
