National Park police launched a rescue effort and emergency services were called in. Ultimately it involved staff from Ruapehu Alpine Lifts, St John Ambulance and Ruapehu Alpine Rescue.
A National Park spokesman said other members of the party witnessed the collapse and were able to give immediate assistance. The first youth was excavated within a few minutes and the second only a couple of minutes later.
An alpine-trained St John paramedic was driven to the site on a snowmobile to provide medical assistance but neither boy was injured.
National Park police spoke with members of the party yesterday to clarify exactly what happened.