As it passes over it is expected to bring damaging 150 km/h gales strong enough to lift roofs, giant 5-metre swells that threaten inundation and erosion along the North Island's east coast and widespread flooding.
Many places will see a month's worth of rain fall in the space of a day while damaging gales wreak havoc.
Conditions are expected to be so hazardous MetService is advising people to seriously consider altering Easter travel plans.
The flood-ravaged Bay of Plenty is already in a state of emergency as Cyclone Cook advances closer to our shores.
Ahead of this a low coming off the Tasman that is packed with heavy rain affecting the South Island before tracking north.
Already rain is starting to fall across the top of the South Island and brushing over the Coromandel.
Civil Defence authorities across New Zealand are warning people to be prepared for the worsening conditions in coming days.
Now there are fresh concerns Cook may make landfall closer to Auckland and the Coromandel sending even more rain over the flood-hit Bay of Plenty.
Weatherwatch.co.nz said international models placed the cyclone making landfall somewhere around Tauranga or Coromandel potentially putting far more people at risk of severe weather.
The MetService is warning after severe flooding in Bay of Plenty last week the region is looking to be one of the worst hit areas, with up to 250mm of rain expected to fall in the next two days.
To complicate matters Cook is likely to dump huge amounts of rain at the end of the week prolonging the rain in already devastated areas.
The Easter storm is unwelcome news for many Edgecumbe residents who remain unable to return to their homes swamped in last week's floods. Others living in rural areas are still cut off.
Great Barrier Islanders are being warned to brace for the worst weather they've seen in recent times.
Intense rain and extremely high winds of up to 165-plus km/h are due to hit the island as Cyclone Cook makes landfall tomorrow.
Auckland Civil Defence head of emergency management operations Aaron Davis said current forecasts showed the cyclone arriving around midday.
"The rain, combined with severe wind and coastal storm surge, could create extreme impacts for Great Barrier Island," said Davis.
"Islanders need to brace themselves for some of the most severe weather they've seen in recent times.
"We know Great Barrier Island is a strong local community that looks out for each other, now is the time for that community spirit to kick into gear. Please spend today planning for this incoming weather and making sure your property is secured, stock moved, and gutters and drains cleared."
Davis said if properties were at risk of flooding or slips, householders should consider ahead of time to stay with family or friends before the storm hits.
