Police and LandSar crews are urging potential hikers of one of the country's most popular treks to ensure they're prepared for the conditions.
Six adults and a 2-year-old suffering hypothermia have recently needed rescuing from the challenging track.
Senior Constables Barry Shepherd of Taupo and Conrad Smith of National Park Police today expressed their frustration about people taking on the crossing with inadequate food and clothing and poor fitness levels. "In the last two weeks Police and LandSar in the Central North Island have rescued numerous people off Mt Tongariro.
"The forecast for this week includes snow down to 700m, which means it will be extremely cold in the mountains and there is a high risk of hypothermia if ill prepared.
"Last weekend two people were rescued and the previous weekend nine people were rescued within Tongariro National Park.
"One of the rescues was a group of six adults and a 2-year-old child. When found some of them were suffering from hypothermia, and rescuers thought they would have died if we did not get to them."