A major upgrade to the eruption detection system on Mount Ruapehu is underway, the Department of Conservation (DOC) says.
In the mountain's last eruption, in September of 2007, two climbers and a snow groomer driver narrowly escaped death in the fast-moving lahar.
The department says about half the eruptions on Ruapehu were not predictable with the old technology.
DOC says new sensors and new communication systems will mean it will be easier to detect eruptions and more information will be conveyed reliably to skiers and staff.
The last major step is the building of a new bunker on the volcano to house equipment.
It will be built above the Whakapapa ski field at an altitude of 2500 metres. Work is due to be completed next summer.
