The volcanic alert for White Island in Bay of Plenty has been raised a notch.
GNS said an eruption was recorded on the Island late last night.
It said the eruption was accompanied by moderately elevated seismic activity, although that was now back to normal.
The eruption appeared to have deposited material over the north side of the crater floor and up onto the north crater wall.
As a result, the White Island volcanic alert level has gone from one to three - which signifies a minor volcanic eruption.