This story discusses family violence. A list of helplines is available at the bottom of the page.
Neighbours believe one child has died, another is seriously injured and their mother has been stabbed in an assault in the Hamilton suburb of Fairfield overnight.
Police were yet to reveal details of what they believe happened, but forensic scientists were examining a house on Douglas Crescent.
Police said they were called to the Fairfield address at 2.10am, following a report of an assault. There they found one person dead and two seriously injured, who were transported to hospital.
"A 34-year-old man was found a short distance from the address with serious injuries and was also transported to hospital, where he remains under police guard," police said.
A neighbour who helped several of the children at the home after the incident said they believed the mother of the children had been stabbed, along with a baby and another child.
Kasey Ritchie said they helped the other children keep warm in a nearby car until police came.
She said they helped as much they could.
Five ambulances, two critical care paramedics and two managers also attended the incident.
"Police would like to reassure the community that this is an isolated incident and there is no ongoing risk to the wider public."
A scene examination will take place.
Police said the 34-year-old will "face charges in due course".
One neighbour Satend Kumar said it is usually a quiet area and the incident was unsettling.
"The first day of the year and we hear the bad news, eh? I don't know what's happened, it's not good, you know, safe for the people around here.
"We haven't seen these things before."
Kumar said he had lived there for more than a year.
"Very nice people and quiet here as well... I don't know what's happened, I feel really sorry for the families, eh?"
Hamilton East MP Ryan Hamilton said it was a tragedy and a reminder to reach out to family and friends at this time of the year.
"This time of year often brings out the best and worst. Our deepest sympathies for all the family involved and friends. It sounds like it's also been a very stressful event for the neighbourhood, so I just trust and hope that they'll get the support they need to work through this this tragic event."
Hamilton paid tribute to the first responders "who had to tend to badly injured children while others were celebrating the New Year".
It was an isolated event with a person in custody, meaning no one else was at risk, he said.
Where to get help:
If it is an emergency and you feel like you or someone else is at risk, call 111.
Women's Refuge:(0800 733 843
It's Not OK 0800 456 450
Shine: 0508 744 633
Victim Support: 0800 842 846
HELP Call 24/7 (Auckland): 09 623 1700, (Wellington): 04 801 6655 - push 0 at the menu
The National Network of Family Violence Services NZ has information on specialist family violence agencies.
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