An unusual cluster of earthquakes has struck beneath Mt Ruapehu's summit since December last year, causing minor volcanic unrest.
GeoNet said in a statement the sequence of tectonic earthquakes has been recorded beneath the summit area since December 31 2021.
"So far, there have been at least 30 distinct earthquakes in this sequence."
GeoNet says compared to historical records these earthquakes are unusual.
"The number of earthquakes with epicentres closely confined to the summit area is unusual," it says on its site.
"While these earthquake clusters are uncommon, none of our monitoring data suggests that the volcano is exhibiting increased levels of activity."
GeoNet will conduct a scheduled gas flight that will sample Ruapehu's Crater Lake this week.
Ruapehu's volcanic alert level remains at 1 which GeoNet says reflects the level of volcanic unrest.
"Volcanic Alert Level 1 indicates the primary hazard are those expected during volcanic unrest: steam discharge, volcanic gas, earthquakes, landslide and hydrothermal activity."
GeoNet says GNS Science and the National Geohazards Monitoring Centre will continue to closely monitor Mt Ruapehu for any further changes.
