Children are feared among multiple people killed in a landslip at a New Zealand holiday park after unprecedented rainfall.

Land gave way above the Mount Maunganui Beachside Holiday Park about 9.30am on Thursday (local time), crushing campervans and a shower/toilet block.

Alister Hardy, a fisherman who was nearby, told the NZ Herald 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.

Another witness, Mark Tangney, said he ran to help when he saw people running from the campground. He told the outlet that he and some other men tried to take the roof off a toilet block, from they could hear people yelling.

“[We] went hard for about half an hour and after 15 minutes, the people that were trapped, we couldn’t hear them anymore,” Tangney said.

An Australian said he was still shaking after finding himself in the middle of the dramatic natural disaster.

Sonny Worrall said he was in the spa when he heard trees cracking. He looked behind to see a huge mountain of earth cascading towards him.

As fast as he could, Worrall, from Newcastle, ran and jumped into another pool.

He could see a “caravan coming right behind me”.

“I was just fearing for my life. It was the scariest thing I’ve ever felt in my life.”

Fire and Emergency NZ spokesman William Pike said the first people on the scene heard calls for help from inside the landslip.

“Members of the public … tried to get into the rubble and did hear some voices,” he said.

“Our initial fire crew arrived and had the same, [they] were able to hear the same.”

Lifeguards at Mount Maunganui – one of New Zealand’s most popular beaches – shared footage of the landslip from above.

Search and rescue experts initially pulled back from the slip, because of the treacherous conditions.

A rescue operation was under way later on Thursday, with officials confirming several people were unaccounted for. Police have not said exactly how many people are missing, only that it is in the “single figures”.

Emergency Management Minister Mark Mitchell described the event as a “tragedy”, saying “parents and the husband of some of the people that we’re currently trying to rescue” were in the campground.

The landslip the heaviest single day of rain on record in the nearest city, Tauranga, with 270 millimetres falling in the 24 hours to 9am.

In nearby Welcome Bay, also near Tauranga, two were also rescued after a landslip hit their house, with one seriously injured, local MP Tom Rutherford said.

Bay of Plenty Police District Commander, Superintendent Tim Anderson, said more people remained unaccounted for. He said there were running concurrent rescue operations.

“Police, alongside Fire and Emergency NZ, are working to locate and rescue people trapped in a landslide that came down off Mount Maunganui at 9.30am today,” Anderson said.

“Work is also continuing to locate two people that are unaccounted for after a slip came down towards properties on Welcome Bay Road overnight.”

Police urged the public to stay away from the scenes.

“The last thing we need is rubberneckers in the area,” Anderson said.

The incidents came after much of the North Island was drenched on Wednesday, with NZ’s national weather service, MetService, issuing a rare red weather warning for a “threat to life” in several regions.

In Warkworth, north of Auckland, 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 continued their search on Thursday, while further east, rescue efforts were under way for stranded locals in the remote Tairawhiti region.

In Te Araroa, people were trapped on rooftops. 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.

Thousands of people in Northland, Coromandel, Bay of Plenty and Tairawhiti were also left without power from the storm and flooding.

MetService reserves its red warnings 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. It killed 11 people and caused $A8 billion in damage.

-with AAP