A man and a woman from New South Wales have been confirmed dead in a New Zealand helicopter crash as atrocious weather conditions force rescue crews to suspend the operation to recover bodies.

Key points: Poor weather delayed recovery efforts, three bodies retrieved

Poor weather delayed recovery efforts, three bodies retrieved Weather heavily overcast at time of crash

Weather heavily overcast at time of crash Two Australian and four British tourists reportedly killed along with local pilot

Pilot Mitch Gameren, 28, and six tourists — including a man and a woman from New South Wales — were killed when the aircraft crashed into rugged and heavily crevassed terrain at Fox Glacier on New Zealand's South Island on Saturday morning.

The two New South Wales victims were identified as 27-year-old Sovannmony Leang and 29-year-old Josephine Gibson.

Josephine Gibson, 29, left, and Sovannmony Leang, 27, right, both from New South Wales, were killed in the helicopter crash.

The four Britons killed in the crash have been identified as Andrew Virco, 50, Katharine Walker, 51, Nigel Edwin Charlton, 66, and Cynthia Charlton.

The pilot had only recently returned to New Zealand after flying Medevac missions in Malaysia.

Earlier New Zealand Police released a statement saying the two Australian victims were women from South Australia, but later issued a clarifying statement.

Three victims have now been recovered from the crash site and taken to a temporary mortuary near the crash site for formal identification, which could take a number of days.

Police described conditions on the Fox Glacier as "dangerous" and said it could take two or three days to retrieve all of seven victims.

Heavy rain overnight and this morning had kept crews grounded, but a break in the weather this morning allowed members of the Alpine Cliff Rescue Team to take off with specialist equipment which allowed them to work in the deep ice crevasses at the top of the glacier.

Mitch Gameren, who reports say was the pilot of a helicopter that crashed on New Zealand's Fox Glacier with six passengers on board, including two Australians. ( Facebook )

Air accident investigators had planned to fly to the glacier before conditions deteriorated and the recovery operation was ended for the day.

Inspector John Canning said recovery of the bodies would take priority over the accident investigation.

He said the recovery operation would resume when conditions improved, but the immediate forecast was not good.

"The weather has turned bad at the top of the glacier," Inspector Canning said.

"The conditions up there are dangerous, so we've got to take our time and ensure the safety of our staff is paramount.

"Our plan is to go forward and recover the remaining bodies up there in the next day or so. It could take two or three days."

Turnbull expresses sympathy to family of victims

The sightseeing helicopter plunged into the Fox Glacier, a popular tourist site on the west coast of the South Island, with weather conditions reported to be heavily overcast and raining at the time.

The wreckage was found in a crevasse but rescuers had difficulty reaching it due to the rugged terrain.

Fox Glacier on the South Island of New Zealand. ( AAP:Tracey Nearmy, file photo )

Prime Minister Malcolm Turnbull said he had spoken with New Zealand's prime minister John Key about the accident on the sidelines of the ASEAN Conference in Kuala Lumpur.

"Our thoughts and prayers are with their families and we're very sorry to hear of that accident," he said.

The Squirrel helicopter was operated by Alpine Adventures, which said it took off on a scenic flight on Saturday morning.

The alarm was raised late on Saturday morning when an emergency locator beacon was activated.

Debris was later found spread over several hundred metres with the main part of the aircraft wedged between house-sized blocks of ice.

The New Zealand Rescue Coordination Centre sent four helicopters to the glacier where they found a deep scorch mark leading to the helicopter about 762 metres up the glacier.

In 2010, a plane headed for Fox Glacier crashed while taking off from a nearby town, killing all nine people on board, including four international tourists.

Alpine Adventures has been taking tourists to the site since the 1980s.

ABC/wires