• Five people, including the attacker, were injured in the incident
  • The motive behind the stabbing remains unclear
  • The supermarket chain said it was "shocked and devastated by the events"

A stabbing incident at a supermarket in New Zealand has left five people injured, with three of them in critical condition. The suspect entered the Countdown supermarket in the city of Dunedin on Monday and randomly attacked people with a knife.

The five people - including the attacker - were taken to Dunedin Hospital immediately afterward. Police arrested the suspect following the incident, BBC reported. Two supermarket staff members were among those injured. Police told reporters that those in critical condition will be undergoing surgery.

Before police arrived at the scene, bystanders apprehended the man who carried out the attack, Superintendent Paul Basham said.

"It's nothing short of heroic," Basham told Canberra Times after reviewing CCTV footage. "Those that intervened, some of whom became injured themselves, acted selflessly and with great courage."

Prime Minister Jacinda Ardern also praised the public's act of heroism. He said that while the motivation for the attack had not been established, there was no evidence so far to suggest it was domestic terrorism.

“Needless to say that such an attack is hugely concerning, and I do want to acknowledge the really early reports of courageous acts by bystanders who have taken action in order to protect those around them,” Ardern said. “Our thoughts are with all those affected by this attack.”

The attacker was "quite a messy little fellow" with curly hair, witnesses told news website Stuff. Police said the suspect is receiving treatment at the hospital and is yet to be formally questioned or charged. 

"This was a fast-moving and extremely traumatic event for every person in that supermarket - the victims who were injured, those present who tried to intervene and those who had to flee to a place of safety," Basham said. "On the face of what we currently know, we believe this was a random attack."

In a media statement, the supermarket chain said it was "shocked and devastated by the events" in the store.

"Our priority right now is our injured team members and caring for our wider team in the wake of this extremely traumatic event," it said. "We are deeply upset that customers who tried to help our team members were also injured."

The statement said the store will remain closed for the rest of Monday and on Tuesday.

New Zealand flag This is a representational image. Photo: AFP / Marty Melville