A surveillance camera at White Island has captured a small eruption at its crater lake, raising the Volcanic Alert Level to a stage two.
During the past week, the Institute of Geological and Nuclear Sciences (GNS) has reported an increase in volcanic activity and gas levels at the island.
Images from a web camera between 4.54am and 4.57am on August 4 reveal a small eruption from the Crater Lake.
Today, the Aviation Colour Code has been changed to Orange, meaning that the volcano is "exhibiting heightened unrest".
A white steam plume at the crater lake can sometimes be seen from areas of the Bay of Plenty coast.
Last Saturday, the lake level in the Crater Lake rose by about three metres to five metres and a volcanic earthquake was also recorded indicating an eruption may have occurred at that time.
GNS volcanologists say that a flow of gas and steam has been present through the lake and from vents near the lake since then, along with an increase of sulphur gases in the steam and volcanic gas plume.
Since early July there have been intermittent periods of volcanic tremor, becoming more continuous since July 28.
Volcanologists say that although these phenomena are not unknown for White Island, this is the first substantial confirmation that small scale eruptions are now occurring on the island.
The Bay of Plenty Civil Defence Emergency Management Group is monitoring volcanic activity in the region.
People visiting the island are reminded that White Island is an active volcano, and eruptions can occur at any time.