Heavy rain has already pounded parts of the country, causing mass flooding and landslips.
And now a cyclone is threatening to bring more weather chaos - Hola waslast night listed as a Category 4 storm, likely to become a fierce Category 5 by the weekend.
Yesterday's deluge closed roads around Hawke's Bay, including Napier-Taupo Rd.
People were evacuated from parts of the Hawke's Bay including students at Hukarere Girls' College and about 20 people from the Eskdale Holiday Park.
Callum Goodall and his father-in-law Grahame Strong called a friend with a boat to pick them up after water flooded the property to about chest height.
"It was like a constant tide coming over the paddock," Goodall said. "The cows were just floating, they were just swimming over the fence."
About 60 Havelock North Intermediate students were also evacuated from a school camp at Weka Pt, Rissington. Principal Julia Beaumont said the two classes went to the camp on Wednesday, but the school decided to return them home yesterday.
"They're really tired, they had a rough night."
State Highway 5 between Napier and Taupo was closed, as were Makahu, Glengarry and Waipunga Rds.
Photos and footage captured by members of the public showed the extent of the flooding - and the damage it had caused.
Vehicles were half-covered by floodwaters and masses of debris, rocks and logs had been brought down in landslips.
More than 20mm of rain per hour fell in parts of Hawke's Bay yesterday.
A Hawke's Bay Regional Council spokesman said water levels for the Esk River were the highest anyone had seen since 2010.
The first hints of a wet week came with what a MetService forecaster called a "thunderstorm cell", which brought 28mm of rain to Napier in an hour early on Tuesday night.
The 41.6mm of rain recorded for the whole day in Napier was equal to about two thirds of the March average for the city and contrasted with the less than 1mm recorded in Hastings.
However, a meteorologist said there were other isolated bands of wet weather in the region, including some hail.
It was the first significant rainfall recorded in Napier in more than three weeks, although 2mm was recorded on February 26.
Heavy rain was also expected this afternoon easing to occasional showers with continuing southerly winds, strong in exposed places.
People in and around the Esk River were being warned to get ready to move quickly if the weather worsened, particularly as rain was forecast to continue overnight.
Other residents in the area had already self-evacuated.
Meanwhile, at Whakahoro, 120 people will have to stay overnight at the Blue Duck Lodge after heavy rains caused landslips; blocking off surrounding roads and tracks.
Ruapehu Emergency Management Officer Nick Watson said slips on the road and a flooded river had cut access to the lodge.
Power had been cut off and there was no water.
Photos and video footage posted to the Blue Duck Station's official Facebook site showed the scale of the damage - fences brought down and tracks closed off by debris.
"A big destructive storm [came] through yesterday at Blue Duck Station," a man behind the camera says.
"So we're going to need diggers, fences. I think we'll need a helicopter to fix some of this. Maybe some regrassing and reseeding a lot of these slips. It's going to be a bit of a major.''
Meanwhile, weather experts say a cyclone forming in the Pacific is forecast to head to New Zealand this weekend.
Cyclone Hola had last night turned into a Category 4 storm, according to the Fiji MetService.
Winds could reach up to 300km/h as it hits Vanuatu before heading to New Zealand this weekend.
The cyclone was still strengthening, WeatherWatch said, and may likely become a Category 5 storm, the strongest kind of cyclone.
This latest cyclone comes just over two weeks after ex-Tropical Cyclone Gita hit parts of the South Island after ripping through Samoa, Tonga, parts of Fiji and New Caledonia.