Police say a 24-year-old man is in custody following an assault, which left two people hospitalised, at a dairy in the Auckland suburb of New Windsor on Thursday morning.
In a statement, Detective Inspector Glenn Baldwin said emergency services responded to reports of someone being stabbed at a dairy on New Windsor Road about 10.40am.
A number of people were in the shop at the time and they managed to intervene and restrain the offender, he said.
They also helped the injured man and a woman who was also injured, he said.
Both victims were taken to Auckland Hospital and the man is in a critical condition, while the woman is in a stable condition, he said.
Police have taken a 24-year-old man into custody.
Baldwin said police remain at the scene, which is near a busy intersection with Maioro Street.
Police were still in the early stages of the investigation and would provide further updates when they could, he said.
A nearby resident, Gary, said he was shocked to hear what unfolded and was contemplating moving.
"Now it's happening on the doorstep, I think it's time to move out, getting too close to home."
He said he was not worried for his safety but his wife would be because she regularly went for walks in the area and it was concerning it happened during daylight.