The plan, a Twin Otter aircraft, was carrying three people from the South Pole to an Italian base at Terra Nova Bay when it crashed Wednesday, CNN reported.
The plane "appears to have made a direct impact that was not survivable," Maritime New Zealand said Saturday.
The plane's operator, Calgary-based Kenn Borek Air, said in a statement the crash appeared to search and rescue crews to be "not survivable," CBC News reported.
"The sighting was confirmed approximately thirty minutes later by a Kenn Borek Air Ltd. Twin Otter aircraft deployed in a search and rescue role," the statement said. "The crew of the SAR Twin Otter reports that the overdue aircraft impacted a steep snow and ice-covered mountain slope. No signs of activity are evident in the area surrounding the site, and it appears that the impact was not survivable."