A 10-year-old boy rushed to hospital after a suspected accidental hanging was playing a game with a hammock when he was injured.
Emergency services were called to a Mangawhai Heads address just after 10am.
St John spokesman Robbie Walker said an ambulance was sent to the scene but the boy was in a critical condition and had to be airlifted to hospital.
The boy was flown to Starship Hospital by the Northland Emergency Services Trust Rescue Helicopter.
A statement from police on Tuesday evening said the boy was playing a game on a private property when the accident occurred.
"It was initially thought that the child had been playing on a swing. It has now been established that a swing was not involved.
"A piece of chain which attaches to a hammock was next to the swing and the boy was playing a game with this.
"We are doing everything we can to assist the boy's family during this difficult time."
A rope swing with a blue seat is hanging from a balcony at the front of the house, which is on a hill overlooking the beach.
Police have removed a chain hanging from under the balcony, next to a swing.
The incident happened on Heather St. A source said it appeared the injured boy was on holiday in the area, and did not live locally.
The Mangawhai Volunteer Fire Service were first on the scene and administered first aid.
A local doctor got to the house soon after and took over.
A Fire Service spokesman said police were now at the house.
Out of respect for the boy's family he did not want to comment further.
Mangawhai residents were shocked to hear about the incident.
"Praying for this kid and his family," one woman wrote on social media.
A neighbour said a family with kids had lived at the property "two or three months", and believed they were renting.
He said he heard children playing this morning and emergency services were focused around the driveway area when they arrived at the home.
Another neighbour, Grant Salmon, said the ambulance crews worked on the boy for about an hour before he was taken in the helicopter.
"It's a tragic accident. Kids will be kids and they get up to all sorts of mischief, but you never want to see something like that happen."
"The house is rented and we don't know the people but they just come and go, it's just tragic that something like this could happen."