Six climbers are believed to be in trouble on Aoraki Mt Cook.
The climbers, believed to be Australians, are reported to have triggered an emergency beacon.
Few other details are known but it is understood search and rescue is assessing whether a rescue operation is possible.
Avalanche conditions on Mt Cook are said to be extreme and the hazardous weather means it is too dangerous for helicopters to fly.
The Rescue Co-ordination Centre says a beacon was activated just after 10pm Thursday. The only people they know of in the area are a party of six who planned to traverse Annette Plateau from Barron Saddle to Mueller Hutt.
Rescuers have not been able to locate the party and conditions are poor, with heavy snowfall and very limited visibility.
Land search and rescue teams can't go in because of the
avalanche risk but a helicopter and specialist alpine search and
rescue team is on standby at Mount Cook, waiting for a break in the
weather.
