Authorities are liaising with the Australian and British embassies, New Zealand police said, though formal identification is expected to take some time.

In a statement on Saturday night, Foreign Affairs Minister Julie Bishop said she had spoken to the families of the two Australians believed to be on board.

"My sympathies are with the families of the crash victims at this very distressing time," she said.

"I am advised that the location and weather conditions at the crash site are difficult and full details of the crash are yet to emerge.

"My department will remain in close contact with the New Zealand authorities as they respond to the crash and we will provide support to any affected families."

Weather conditions were too bad on Saturday for crews to reach the scene where the helicopter crashed, in a crevasse 750 metres up a valley, to recover the bodies of those killed.

Inspector John Canning said  recovery would be very difficult in the dangerous terrain, where debris was scatted hundreds of metres around the crash site.

"I'm not going to risk any more lives, we've lost seven," he said.

Earlier, four choppers responded to the crash site and winched a paramedic and a rescuer down to the scene to see if anyone had survived the crash.

It was understood the company involved was called Alpine Adventures.

Vince Cholewa, from the rescue centre, said two choppers had flown from Christchurch, one from Greymouth and one from Fox Glacier, with a cliff rescue team on board.

Cholewa described the area as "heavily crevassed".

Glacier Country Tourism Group member Chris Alexander said emergency services had tried "their damnedest" to reach the scene.

There was cloud and rain in the area where the crash occurred, MetService said.

New Zealand's Transport Accident Investigation Commission has opened an inquiry into the incident.

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