A helicopter carrying five people has crashed about 35km northeast of Waiouru this morning, injuring all occupants.
The Civil Aviation Authority confirmed to 1 NEWS the helicopter crashed just before 9am today.
A spokesperson from Transport Accident Investigation Commission has confirmed to 1 NEWS five people were on board, including the pilot.
Two men, both aged in their 40s are in a critical condition, Hawke's Bay District Health Board has confirmed to 1 NEWS.
Anther man, aged in his 30s is in a serious condition.
Two other men with less serious injuries were assessed by St John upon arrival at Bridge Pa airport by rescue helicopter.
The CAA is sending three investigators to the scene this afternoon.
1 NEWS understands the Defence Minister has been informed by NZDF that the helicopter is not one of their aircraft.
The crash occurred at Ngamatea Station in the Kaweka Ranges.
The Rescue Coordination Centre which coordinated the response to the crash says it was a commercial helicopter undertaking a commercial survey operation in the area.
At 8.50 am, RCCNZ received an alert from the distress beacon on board, providing a location at Oturua Stream.
RCCNZ Search and Rescue Mission Coordinator Dave Wilson said another helicopter from the same company was initially sent to provide a fast, initial response to determine the situation, with the Greenlea Rescue Helicopter from Taupo arriving on scene soon after to provide medical care.
“Distress beacons can summon life-saving help to people who need it and get them to hospital faster. In this particular case, the alert from the distress beacon was the only notification that the aircraft had crashed," Mr Wilson said.
RCCNZ tasked two additional rescue helicopters with intensive care paramedics - one from the Hawke's Bay Helicopter Rescue Trust and the Palmerston North Rescue Helicopter.
"Our thoughts are with the injured passengers and we wish them a successful recovery," Mr Wilson said.
Obviously they were very relieved to have some assistance at that point- Nat Every from Taupo's Greenlea Rescue Helicopter
The circumstances around the crash are still being established and the Transport Accident Investigation Commission is investigating, he said.
One of the first rescue helicopter crewmen to arrive on the scene says the casualties were very relieved to have some assistance.
Nat Every from Taupo's Greenlea Rescue Helicopter told 1 NEWS that at about 9am this morning they were alerted by the RCCNZ to an active emergency locator beacon in the south eastern Kaimanawa Ranges.
"We responded from Taupo with an intensive care paramedic on board, crewman, SAR personnel, just to make sure we were fully catered for whatever situation on scene," Mr Every said, speaking after landing at Hawke's Bay Hospital.
"It was the bottom of a valley, a reasonably open valley in the edge of the Kaimanawa Ranges. And obviously this incident had taken place. And upon arrival it was just a case of doing the best we could and treating the injured people with the personnel we had and seeking the reinforcements we needed to successfully complete this task," he said.
"There are a range of injuries ranging from relatively uninjured to very seriously injured. And obviously they were very relieved to have some assistance at that point.
"So intensive care paramedic treated the patients as best he could at that point in time and we sought reinforcements to help with the transfer and the treatment of additional patients."