A landslip on Thursday morning at a campground in tourist hotspot Mount Maunganui left "several people" unaccounted for, according in NZ Police.
A man was swept away in Warkworth, in Auckland's north, on Wednesday, while others have been dramatically rescued in the big wet.
Huge swathes of North Island were drenched on Wednesday, with meteorologists MetService issuing a rare red weather warning for a "threat to life" in several regions.
The storm delivered buckets of rain, with virtually all of the Coromandel peninsula receiving over 200mm on Wednesday and the Bay of Islands drenched by over 150mm.
Tauranga - the closest city to Mount Maunganui - received 295mm of rain in the 30 hours to 6am, before the landslip around 9:30am.
Local media reported screams at the Mount Maunganui Beachside Holiday Park, where the landslip hit campervans and a shower/toilet block.
Lifeguards at Mount Maunganui - one of New Zealand's most popular beaches - shared footage of a landslip on the mountain, which also hosts well-loved walking trails.
Nearby fisherman Alister Hardy told the NZ Herald said he heard "rolling thunder and cracking of trees", before looking up and seeing "the whole hillside gave way".
"There were people running and screaming and I saw people get bowled. There are people trapped," he said.
In Warkworth, a man aged in his 40s driving his car was swept away in the swollen Mahurangi River, while a passenger was able to scramble to safety.
Police are continuing their search on Thursday, while further east, rescue efforts are underway for stranded locals in the remote Tairawhiti region.
People have been trapped on rooftops in Te Araroa, with Mark Law - the helicopter pilot involved in rescue efforts after the deadly 2019 Whakaari-White Island volcanic eruption - told Radio NZ he was helping to conduct checks in the area.
Another couple in Welcome Bay, near Tauranga, were also rescued after a landslip hit their house, with one seriously injured, according to local MP Tom Rutherford.
Thousands of people, in Northland, Coromandel, Bay of Plenty and Tairawhiti, were also left without power from the storm and flooding.
The red weather warnings issued by Metservice are reserved for only the most concerning events.
This week's alert is the first rain-related red warning to hit the same area since Cyclone Gabrielle in early 2023, killing 11 people and causing $A8 billion in damage. Â
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