Emergency services in New Zealand are searching for several people, including a child, believed missing after a landslide hit a campsite during storms that have caused widespread damage across the North Island.

Emergency minister Mark Mitchell told RNZ that parts of the east coast looked like “a war zone”, with helicopters deployed to rescue families sheltering on rooftops from flooding, and local states of emergency declared in five regions across Northland and the East Cape due to days of record-breaking torrential rain.

The landslide struck on Thursday morning at a campground in the tourist hotspot of Mount Maunganui on the east coast. Mitchell confirmed that a young girl was among those unaccounted for.

The aftermath of flooding that hit Punaruku in New Zealand’s North Island. People had to be rescued from their rooftops, said firefighters. Photograph: Tairāwhiti Fire and Emergency New Zealand

“It’s a fluid and sensitive issue at the moment,” he said. “Everyone is working as hard as they can to get the best possible resolution possible, but in no doubt at all it is a very difficult and challenging situation.”

Footage from Mount Maunganui revealed overturned camper vans and upturned trees. Witnesses told local news outlets they heard an incredibly loud noise before seeing a large chunk of hillside hit the campsite.

Tauranga – the closest city to Mount Maunganui – received 295mm of rain in the 30 hours to 6am, before the landslide hit around 9.30am.

A landslide at Mount Maunganui has caused widespread damage. Photograph: Alister McHardy

An Australian man, Sonny Worrall, narrowly escaped the landslide while swimming in a nearby pool. “As I’m swimming I heard this huge landslide behind me, trees cracking, there was a caravan that almost hit me. I had to dive in the next pool,” he told news outlet Stuff. “It was the scariest thing I’ve ever felt in my life,” he said.

In Papamoa, south of Mount Maunganui, one person suffered serious injuries and another two people are missing after a landslide hit a home at 4am on Thursday. Police are resuming efforts to find a man in his 40s who was swept away at a river crossing near Warkworth, north of Auckland, on Wednesday.

Images soon began circulating showing flooded houses, farmland and community centres and roads cut off by landslides, and stories of harrowing escapes and incredible rescues are emerging. A community came to the aid of a 94-year-old man trapped by flood waters in Coromandel, while a woman was rescued by kayak as neck-high, fast-flowing water surrounded her home.

Tairāwhiti Fire and Emergency said it had rescued people from rooftops. Its photos showed houses inundated with logging waste, mud and water, and cars and fences largely buried.

“These are not training images,” the department wrote. “This is Punaruku, Te Araroa, this morning.”

Damage from a landslide on Mauao, at Mount Maunganui. Photograph: Alister McHardy

Prime minister Christopher Luxon said the government was doing everything it could to support those affected by the extreme weather and thanked emergency crews for their efforts. “All those who are putting themselves in harm’s way to keep Kiwis safe, the whole country is grateful,” he said.

A tropical low is expected to bring more heavy rain on Thursday, the National Emergency Management Agency said. “Rain is falling on ground that’s already saturated, meaning impacts like fallen trees, landslides, flooding and dangerous river conditions are more likely.”