Two snowboarders missing for six hours had to be rescued in “extremely challenging” conditions after deciding to go off-piste near Treble Cone.

It’s the second time this week Wānaka police have had to coordinate a search and rescue operation involving people in the alpine environment, and they are warning skiers and snowboarders not to venture into back country areas unless experienced.

Sergeant Darren Cranfield, of Wānaka, says about 1.45pm on Thursday, police were notified of two snowboarders in need of help near Treble Cone ski field.

The pair had gone beyond the boundaries of the ski field to explore the back country before becoming lost for approximately six hours.

"At the time, weather conditions were extremely challenging, with heavy snowfall, strong winds and near-zero visibility,” he said in a statement today.

”The search was complex and required the expertise of the Wānaka Alpine Cliff Rescue Team, multiple ski patrol units and an aerial search team.

“Aspiring Helicopters operated in very difficult flying conditions, and it was only through the pilot’s extensive local knowledge, experience and exceptional flying skills that search teams could be safely deployed into the alpine environment.”

The snowboarders were located approximately one hour before nightfall. “Had they not been found before darkness, the outcome could have been significantly more serious,” Sgt Cranfield said.

“Police are incredibly grateful for the professionalism, dedication and expertise of everyone involved in the search.

“Wānaka is fortunate to have such highly skilled volunteer and professional rescue personnel who are prepared to respond in difficult and often hazardous conditions to assist those in need.”

Sgt Cranfield said the incident was a timely reminder that venturing beyond ski area boundaries into the back country should never be taken lightly.

“Anyone planning to enter the alpine environment must have the necessary experience, understand the current weather and avalanche conditions, carry appropriate emergency equipment and have the skills to use it.

”Even a minor mistake can quickly develop into a life-threatening situation in alpine terrain.”

Earlier this week,  a climber spent three hours battling to the top of Otago’s highest peak believing his companion had plummeted to his death.

The duo, an Australian and a New Zealander, were descending the west face of Mt Aspiring near Queenstown on Tuesday after earlier reaching the summit when the New Zealander fell 200m down the cliff face into a crevasse, Helicopters Otago chief executive Graeme Gale said.

Sgt Cranfield said the climber's companion was faced with an extremely challenging situation.

"After the fall, the companion spent more than three hours climbing in difficult alpine terrain to find enough satellite reception on a mobile phone to raise the alarm. During that time, they too were becoming increasingly at risk of hypothermia."

A search and rescue operation was immediately initiated, with the Otago Lakes Search and Rescue and Heli Otago tasked with locating and rescuing both climbers about 1am.

- Allied Media