A woman was seriously injured this evening in a suspected gang dispute in which two cars collided.
An eyewitness said debris was strewn across Masterton's Miriam St near a damaged car and armed police had cordoned off the road.
The eyewitness said at 6.15pm a rescue helicopter was flying overhead and multiple police cars had their sirens wailing.
Police central communications Inspector Dave Rose said the situation in Masterton was "still very dynamic" and officers were trying to piece together what happened.
Mr Rose said gang members were in the area when police arrived.
He said the woman had injuries that suggested a car had possibly struck her, but this was not yet confirmed.
The woman was flown to Wellington Hospital and was in an intensive care unit. Mr Rose said the injured woman was not able to talk.
Police said several people called 111 about 5pm to report a woman had been injured "in an altercation where gang members were present".
Police were still at Miriam St just before 8pm and an investigation was underway.
Police said staff from Wellington have gone to Wairarapa to assist with "keeping the situation calm".