'Shouts, then silence' - Children among several missing after massive landslide destroys NZ campsite

But nobody has been rescued from beneath the landslide itself.

Initially, people could be heard shouting out after the campsite was partially buried.

But a second slip threatening to come down meant rescuers had to temporarily call off a search.

No voices have been heard since.

NZ Police Minister Mark Mitchell told the New Zealand Herald that "young people" were among those unaccounted for, calling it a "heartbreaking" situation for parents.

Robyn, a resident in a nearby apartment block, told Radio New Zealand she saw people digging through the mud for an hour after the campsite was buried - but it appeared no bodies were found.

She said she saw stretchers arriving, then leaving empty.

Rachel McGarva, another local, said she saw trees shaking and mud sliding down towards the swimming pools in the middle of the site.

She rushed with her family to the scene - and recounted a chilling sight when she arrived.

"People are trapped in the toilet block, and some of the facilities are covered... Some girls trapped in the toilets managed to yell out to their parents," Ms McGarva said.

"The building that had filled with dirt, they are trying to take the roof off and trying to dig. Everyone was just going and trying to dig."

And one more witness said a caravan had been thrown into a pool by the slip.

Geologists are now facing a race against time to assess when it will be safe to access the campsite again.

Police have said the number of people missing stands in the "single figures", adding it is "possible we could find someone alive".

PM Christopher Luxon said he was "actively monitoring situations across the country – including the major incident in Mount Maunganui", adding extreme weather is still causing dangerous conditions across the North Island.

Emergency Management and Recovery Minister Mark Mitchell said on Radio NZ that the heavy rains hit almost the entire eastern seaboard of the North Island.

Heavy rains and a major storm have wreaked widespread damage across the area, with homes being evacuated, thousands left without power and roads closed.

“The good news is everyone responded very quickly. There was time to get prepared, and that helps to mitigate and create a strong response,” Mr Mitchell added.

All weather alerts have now been lifted across the country, apart from a strong wind warning and heavy rain watch for the Chatham Islands, more than 400 miles east of New Zealand's North and South islands.