Fears for the safety of a group of hikers were expressed yesterday after three avalanches tumbled down Mount Ruapehu, forcing the evacuation of Turoa's upper ski field.

One large avalanche, followed by two smaller ones, slipped from near the summit about 3pm.

Nobody was caught in the snowslides, but the Ruapehu Alpine Rescue Organisation made a precautionary search of the area.

Ruapehu police area commander Inspector Steve Mastrovich said his staff reported that everyone who was known to have been near the summit was accounted for last night.

"We're confident everybody is out of the area."

However, there were initial concerns for a group of 35 hikers believed to have been walking towards a "hazardous area" near the slips.

Turoa Ski Area mountain manager Chris Thrupp said ski patrollers reached the group and helped them down safely.

Police said the avalanches did not occur on the ski field, but did encroach onto it.

The upper-mountain lifts were closed and customers were brought down to lower levels.

Because the slips were natural events, Mr Thrupp said it was possible there could be more avalanches in the same area.

"We believe there is risk from some of the other areas up there," he said.

"It's what we call a natural event. We believe it's been caused by the sun heating the new snow and it absorbs moisture and becomes quite dense - a little bit like mud in the rain on a slope; it gets wet, becomes heavy and slides down."

Mr Thrupp said avalanches were not common in the area and staff worked to manage the risk using explosives.

He expected the upper ski field would be reopened today. About 2500 people had been on the mountain yesterday.

- © Fairfax NZ News