Wild weather is hammering Napier tonight, with slips, flooding and leaking roofs causing chaos. Firefighters have been called to assist flooded buildings in the centre of the town, and power is out to many properties.
Civil Defence says dozens of people have been evacuated from the area.
MetService has warned the rain could continue until late on Monday night and more is expected on Tuesday.
Napier City Council has asked residents to reduce strain on the wastewater network, and Unison Power company has reported unplanned outages to more than 2000 properties in the area.
People who need assistance have been asked to call 111 for help, and not Napier Fire Station.
Firefighters have already responded to at least 80 callouts, with another 40 still waiting for help.
Forecasters warned Hawke's Bay residents that up to 130mm of rain could cause surface flooding and driving hazards from this afternoon, when rainfall rates could reach up to 40mm/h during thunderstorms. With "another burst of heavy rain possible on Tuesday."
Napier South resident Amanda said the amount of water was daunting.
"It's just as though there's a river going down the road, and I've lived here off and on since I was three, I've never seen anything like it."
MetService issued a heavy rain warning for Hawke's Bay south of Wairoa from 4pm on Monday, and downpours were expected across other eastern and southern parts of the North Island to Wellington.
RNZ Reporter Tom Kitchin told RNZ's Checkpoint programme today he had been trapped in his office by flooding outside the building and torrential rain.
"The rain is very heavy... I don't want to go outside because I know a whole lot of water will come into the office, it's that bad at the moment. I can see the roads are flooded all over.
"Fire and Emergency NZ are quite busy... they're just getting multiple calls. They've had about 20 calls in the last few hours in Napier itself, a lot of buildings have been flooded, there's a lot of surface flooding, and I'm just hearing sirens blaring all the time at the moment."
Napier City Council said the deluge was causing problems for the wastewater network.
Residents have been asked to avoid flushing toilets, and hold off using showers, dishwashers or washing machines, to try to relieve stress on the network.
The council said an emergency discharge could be made into the Ahuriri Estuary if the system was under too much strain.
It sent out an advisory warning to residents this afternoon, warning the rain that had already fallen could create problems if there was more heavy rain.
"Napier has had 53.2mm of rain today, and a further 34.7mm of rain is expected to fall through to midnight.
"If an emergency discharge is carried out, this should prevent wastewater backing up and overflowing into city streets and properties," the council said.
HEAVY RAIN WARNINGS
MetService warned heavy rain could fall in Hawke's Bay south of Wairoa, and Gisborne until 1am Tuesday.
On top of what had fallen during the day, they said a further 70 to 100mm of rain could fall in the ranges, with 40 to 70mm elsewhere.
Thunderstorms could bring intense downfalls from the afternoon onwards, and could reach 25mm/h to 40mm/h in thunderstorms.
Forecasters warned that more heavy rain could be coming on Tuesday, too.
Heavy rain and thunderstorms could strike Tararua district between 7pm tonight and 7am tomorrow, with up to 100mm of rain possible and downpours up to 25mm/h.
Wairarapa and the eastern hills of Wellington could expect heavy rain from 9pm Monday to 11am Tuesday, with up to 110mm expected in some parts, and intensities up to 20mm/h.
"A front in the east of the North Island should sink southwards during today and tomorrow morning, delivering heavy rain," MetService said on Monday.
"On Tuesday, a low is forecast to track east across the upper North Island, delivering rain to many places."
Heavy rain could hit the Coromandel Peninsula on Tuesday from 6am, and the Bay of Plenty from 11am.
