KEY POINTS:
Police say they are investigating everyone allegedly involved in a brawl outside a south Auckland liquor shop on Tuesday night.
Two Otara shop owners were stabbed in the fight and one youth was taken to hospital after receiving head injuries.
Police said weapons used in the fight included a fence paling, knives and a long bar or bamboo stick.
One of the shop owners reportedly used a hockey stick in the fight.
Detective Senior Sergeant Dave Pizzini said the owner of a liquor shop approached a drunk youth who he suspected of shoplifting. A fight broke out shortly after.
Mr Pizzini did not rule out the possibility that the shop owners and youths could face charges.
"We are investigating the criminal liability of everyone involved," he said.
Shop owners were able to use "reasonable force" to defend themselves and their properties but he urged people to use their common sense.
The two liquor store owners, Baljeet Singh, and his cousin, Varinder Singh Bains, were stabbed as they held one of the teenagers until police arrived.
One of the teenagers was injured but three others ran away, hitting neighbouring dairy owner, Harvinder Kalkat, in the face with a piece of wood as they fled.
Her daughter said angry teenagers had threatened shop owners just days before the fight, saying they would return to "cause trouble".
Tanjot Kalkat told the Herald some youths had gathered outside the shops on Sunday night, yelling abuse and threatening people.
"They were swearing at the wholesalers and starting fights. We rang the police. [The youths] said they would be back to cause trouble," Miss Kalkat said.
Miss Kalkat said her mother came out of her dairy on Tuesday night when she heard a window break and was hit in the head with a wooden stick.
"She's not coping very well, she's in pain," Miss Kalkat said.
She said her mother's eye was puffy and she had a couple of stitches.
While they hadn't had any trouble at the dairy in 15 years, the incident had left the family feeling unsafe.
"There are heaps of youth gangs. We see them when we close the shop," she said.
Mr Singh and Mr Singh Bains were recovering from their stab wounds but didn't want to talk about the ordeal yesterday.
The youth who received head injuries had been discharged from hospital and was expected to be interviewed by police last night.
Mr Pizzini said it was a "serious concern" to police that people as young as 16 were walking the streets drunk and with knives.
"It was only yesterday Judge Becroft featured on the front page of the Herald talking about the escalation in serious youth violence."
Ten detectives and uniformed staff were looking for items of clothing seen on CCTV cameras. A knife believed to have been used in the attack had been recovered.
"Officers are interviewing witnesses, canvassing neighbours, locating weapons and suspects. Some search warrants are being executed," Mr Pizzini said.