They were pilot Tim Brown and guide Sean Roach.
Alpine Group Limited confirmed the two deaths in a statement about 2.20pm today.
The statement said an Alpine Group aircraft had been involved in an accident in the upper Te Naihi River, South Westland, at 9.39am yesterday.
It had been conducting a guided hunting operation in clear and calm conditions, Alpine Group Limited said.
"Our thoughts and deepest sympathies are with their families and loved ones during this difficult time," the statement said.
"We respectfully ask the media to respect the privacy of the families as the process this."
Investigation under way
An investigation began this morning into yesterday's crash.
Transport accident investigation commission senior communications advisor Simon Pleasants said the crash was reported to have happened halfway between Mt Aspiring and Mt Victor, about 24km west of Makarora.
"We have a team going to Queenstown this morning, if conditions permit, they will fly to the accident site," he said.
"Then tomorrow and Wednesday there will be a team on the mountain collecting evidence."
Mr Pleasants said the first evidence they were looking to gather is what can disappear or change in the environment.
"We need to make sure we gain good knowledge about what is lying here early on.
"This applies to human factors too, memories of people who were on board," he said.
The team plans on getting on to the mountainside "as soon as possible" and deployment will last at least three days.
The wreckage will later be removed from the mountainside and will sent to the technical facility in Wellington.
Mr Pleasants said their thoughts are with the families of those involved.
A police spokeswoman said police understood the three survivors were on the ground at the time of the crash.
"Police are not aware of any injuries sustained by the three surviving members."
Police initially issued a statement at 3.13pm yesterday saying two people had died in a helicopter crash.
The first reports of the crash had come in at 9.50am, the statement said.
Alpine Group is owned by the Wallis family.
Two Wallis brothers, Matt and Nick, were killed in separate helicopter crashes in 2018.
Brother Toby is the chief executive of the company and the other brother, Jonathan, is the general manager.
The Wallis men are the sons of aviation pioneer and Warbirds Over Wānaka airshow founder the late Sir Tim Wallis and his wife, Prue, Lady Wallis.
Police said Maritime NZ’s Rescue Co-ordination Centre had handed responsibility for the response to police, who were on scene yesterday afternoon.
Detective Sergeant Sarah Waugh, of the Cromwell CIB, earlier said police inquiries were ongoing.
‘‘I can now confirm the helicopter was a chartered craft, and the occupants were on a hunting trip.
‘‘The two people who died were the sole occupants of the craft at the time.’’
Three others from the hunting group were located on the ground and taken to safety, she said.
‘‘Our condolences go out to their loved ones, who we are providing support.’’
Their deaths had been referred to the coroner, and the Civil Aviation Authority and the Transport Accident Investigation Commission had been notified.
A spokesman for the Civil Aviation Authority said in a statement last evening it was aware of the accident and ‘‘are making initial inquiries to understand the circumstances and are liaising with other agencies involved’’.
‘‘Our thoughts are with the families and loved ones of those affected at this difficult time,’’ the spokesman said.
— additional reporting Allied Media
