An eyewitness to Tuesday's helicopter crash north of Kaikōura that killed two people has described the scene as one of carnage.
Three others seriously injured were airlifted to Christchurch Hospital.
Emergency services raced to the crash, described as a "grey mess" on the beach at the Kekerengu river mouth.
Five people were in the helicopter - the pilot and four passengers, police said.
"I just saw a helicopter coming in to land, and then it got out of control, started twisting around and around, then did the dive, bang, onto the beach," witness Ian Mehrtens told Checkpoint.
Mehrtens, who owns a Bed and Breakfast nearby, was one of the first at the scene. He jumped on his quadbike and raced to help when he saw the helicopter plunging toward the ground about 100 metres away.
"I could see the whites of their eyes, put it that way."
The scene was "carnage" he said. "Helicopter on its side, people screaming, people on the beach, there were quite a few helpers there so that was really good.
"We got the people out of the helicopter and made them comfortable until the authorities arrived."
Mehrtens helped four people out of the helicopter but did not know in total how many there were.
"A family - three children, and I think one adult was the mother.
"Probably the youngest would be seven or eight. The young fellow would be about 10 and the other girl would be in her teens.
"I think they were just coming in to land to have a cup of coffee basically at the store - that's what happens quite regularly - and I think something may have just gone amiss on his way down.
"I'd say he would have been about 20m, maybe 30m, then that's when it all happened."
Helicopter scenic flights are frequent in the area, he said. He did not recognise the crashed chopper.
"I don't even know what brand or who runs it or anything, just that it was a big grey mess on the beach.
"It was mangled, it was on the side - rotor blades and perspex screens everywhere, belongings everywhere. I would have been about the fifth or sixth on the scene I suppose."
The crash was just on the edge of the water, he said, at the low-tide line.
"We had to walk in the water to get them out… Really awkward because there was nothing to get up on the helicopter to pull them out. In the panic you just jump up and do it."
He said at that time there were three or four from the crash who were conscious and nothing sounded unusual before the crash.
"Then all of a sudden, twist, twist, round and around then [it] dived down into the surf."
Eventually three helicopters turned up to help, with Fire and Emergency, police and ambulances there too, he said.
For about 90 minutes after the crash Mehrterns was comforting the people on the beach.
"Just as you say, it's okay… the wee one was saying 'my mum, where's my mum'. I said, 'your mum's okay'. Whether she was or not I do not know."
Another person early to the scene knew first aid and was able to help, he said.
"There was a tourist, he was with his family… He was excellent.
"He directed people and made sure everyone was okay, and made sure that the people who are looking after the injured were all okay, organising blankets and stuff like that to keep them out of the breeze, keep them warm.
"Someone managed to get a first aid kit and bandaged a young kid's head up."