A rugby coach says machetes, axes and knives were used in a violent post-match brawl in Wairoa on Saturday that police have described as "appalling".
At least two people were moderately injured after being stabbed and two people were hit by a vehicle in a fight that broke out between teenagers and descended into a public brawl involving dozens of people - including Mongrel Mob gang members, police said.
Extra police have since been brought into Wairoa, including tactical dog teams.
Hosts Tapuae Rugby Club had taken out the "high quality" match against YMP from nearby Raupunga 26-7, and players were in the changing rooms getting ready for after match celebrations when they heard a disturbance outside, YMP coach Guy Taylor said.
"We went out and there was a large number of people sort of yelling and bottles were flying," he said.
"What we understand is ... quite a large contingent of Mongrel Mob had descended upon our supporters, as they were getting ready to leave."
There were about 30 people on each side, and YMP supporters were being attacked, with some gang members weilding machetes, axes and knives, he said.
Young kids, women and older men were among those caught up in the brawl, and they were "quite terrified ... very fearful," he said.
"When we went out there, and there were three people beating up one person, we had to intervene, otherwise people could have got seriously, seriously hurt."
Taylor and others tried unsuccessfully to break things up before police arrived.
It is the second time this season YMP have been caught up in gang-related violence after a rugby match. In April, shots were fired at a YMP team van after a match against Tamatea in Hastings.
YMP - a club based in Raupunga, near Wairoa - has several Black Power members on the team, but they were not involved in the violence on Saturday, Taylor said.
The brawl was not about rugby, and should not reflect badly on either club, he said.
It had been a "great family day", a good match, and the teams were looking forward to socialising afterwards.
"It was [an] unprovoked attack on us. I just feel it's like it's an attack on our community," he said.
"The Mongrel Mob have just got to pull their head in, they can't just do this.
"We're trying as hard as we can just to play rugby."
Extra police in Wairoa
The brawl was "an appalling display" following a day of celebration, acting Tai Rāwhiti area commander Inspector Darren Paki said.
"Thankfully nobody was seriously injured or killed in this event, but it is sadly another shocking event that our community didn't need," he said.
Police have identified about two dozen people involved, and a number of arrests will likely be made, Paki said.
"The majority of them are gang members of varying ages, but all of them are old enough to know what's acceptable."
"We are not tolerating this behaviour in our community and police will be making that message very clear to gangs over the coming days and weeks."
Police have boosted their presence in the town, including tactical dog teams, investigators and frontline staff.
"There will be a noticeable police presence across Wairoa to ensure that gang members are held to account for the weekend's incident and any other offending that they may be involved in," Paki said.
Police want to hear from anyone who saw what happened.