Volcanic tremor levels at Mt Ruapehu increased over the past week and are now among the highest seen in nine years.
The Crater Lake (Te Wai ā-moe) temperature has continued to rise, and GeoNet yesterday said the lake was at 36C.
It remains in a state of unrest at alert level 2 - a higher risk of an eruption.
GNS science volcanologist Geoff Kilgour told Morning Report this tells them there's a lot of gas and fluid moving through the volcano.