They were 28-year-old Flying Officer Daniel Stephen Gregory, a pilot; 33-year-old Flight Lieutenant Hayden Peter Madsen, also a pilot; and 25-year-old Corporal Benjamin Andrew Carson, a crewman.
Investigators are this afternoon sifting through wreckage trying to discover why the helicopter crashed.
The Iroquois was on its way from Ohakea Air Base in Manawatu to Anzac Day commemorations in Wellington when it crashed shortly before 6am in rugged terrain near Pukerua Bay, about 40km northeast of Wellington.
Three people died at the scene. A fourth was winched from the scene and transported to Wellington Hospital, where he is in a stable condition.
Dave Greenberg of Wellington's Westpac Rescue Helicopter said the crashed aircraft's was upside down and severely damaged when they found it.
"The emergency beacon from the Iroquois allowed us to get there more quickly than we otherwise would have," Mr Greenberg said.
"We got there to find it upside down. It was unsettling."
Mr Greenberg said the rescue helicopter was getting ready to head to another job when told of the possible crash.
"We picked up a Wellington Free Ambulance paramedic who had experience of being winched down, and he was winched down to the scene where we picked up the injured man."
The Iroquois was believed to be one of three heading towards the Anzac Day commemorations and Mr Greenberg praised the actions of a crew member of another Iroquois who headed to the scene to try to help his colleagues.
"He was dropped down and had to go cross the terrain, maybe up to 2km, to get to the scene. He did amazingly well."
Inspector John Spence, area commander of Kapiti Mana police, said the crash site was difficult to locate in what was low cloud cover and it took some "impressive flying" by the Westpac Rescue helicopter to get close to the ravine and winch someone down.
"As you can imagine for our armed forces, especially the air force, it is an extremely poignant time. This has happened on one of our special days," he said.
He hoped the bodies would be removed from the crash site today but the access and weather conditions made that job difficult.
Mr Spence said he believed the injured man had a dislocated knee and chest injuries. Wellington Hospital confirmed to NZPA the crewman was in a serious but stable condition.
Police search and rescue had taken control of the scene and were working closely with Air Force staff to investigate what happened and to identify and remove the bodies of the three crew, he said.
He said the helicopter "was pretty badly smashed up".
Mr Spence said he presumed the three crew were killed instantly, the fourth man had managed to get out of the wreck and was found nearby.
The Defence Force confirmed late this morning that three people had lost their lives.
Pukerua Bay resident Kathy McLauchlan told NZPA she could see the crash site from her window.
Weather conditions at the time of the crash were "extremely misty", she said.
"Since the mist has lifted we can see it."
The crash happened quite high on the hills overlooking Pukerua Bay, Ms McLauchlan said.
Defence Minister Wayne Mapp reportedly said a fourth person had died in the crash when speaking at an Anzac Day engagement in Auckland, but a spokesman for his office subsequently said he had been given incorrect information.
