Police are concerned for the safety and welfare of 30-year-old William Kerry Power who was last seen at his Dannevirke home around 10pm yesterday (Tuesday, 9 July).
A family member notified Police around 8am this morning of Mr Power's disappearance.
Tararua Senior Sergeant Nathan Davis said: "Police have been speaking to the family of Mr Power to understand his background and as a result of this we are genuinely concerned for his state of mind."
"While initial indications suggest he may have left the house with a firearm we don't believe there to be a threat to public safety.
"If anyone has seen Mr Power we urge them not to approach him but to contact Police," said Senior Sergeant Davis.
A search of the wider area around Mr Power's property was conducted earlier this afternoon by Police. Any further searches are unlikely in the next 12 hours due to the deteriorating weather, however the recommence of a search will be reviewed tomorrow morning.
Mr Power is described as nearly 5'9 in height, of medium build, and fair skin with brown hair and eyes.
He left his house on foot and is believed to be wearing black gumboots, black trousers with white stripes, a khaki green polar fleece top, and a black beanie.
Anyone with any information as to the current whereabouts of Mr Power, or who may have seen him is asked to call the Dannevirke Police on (06) 374 4500 as soon as possible.
Media enquiries should be referred to Communications Manager Sara Stavropoulos on 027 702 0850.