The Armed Offenders Squad have been called out to Wairarapa in response to a firearms threat.
Police were alerted to the threat at a residential address in Martinborough at about 5pm.
Senior Sergeant Pat Thomas said police were searching for one man, understood to be from Martinborough, in relation to the threats.
At 7pm the situation was still "unfolding" and it was believed the man was somewhere in the Wairarapa area in a vehicle.
The Life Flight Westpac Rescue helicopter was sent from Wellington to help in the police search.
It was understood the man had made the threats against someone known to him, Mr Thomas said.
It was not believed any shots had been fired.
Mr Thomas said there was no risk to the public.