Another minor eruption has occurred on Whakaari / White Island overnight.
There has been volcanic activity on the island almost constantly since May, and the last minor eruption was on Friday.
GNS Science duty volcanologist Ery Hughes said it was keeping an eye on ash levels, but no ash was expected to fall on the mainland.
She said GNS has issued a notice to the aviation industry.
Speaking to Morning Report, Hughes said GNS had received information from MetService in the early hours of Tuesday that they could see ash on its satellite images.
It showed ash being emitted from the volcano, and it was continuing - heading north, away from the mainland.
Hughes said the plume not was rising high into the atmosphere, suggesting to GNS that it was a minor eruption.
Given activity had sparked up a bit on Friday and was continuing now, it was expected to continue throughout the week, and possibly even weeks and months to come.
With the activity, sulphur dioxide being emitted also suggested magma was now at shallow levels.
GNZ would conduct monitoring flights, dependent on the weather, to allow experts to have a better visual of what was happening on the island.
Given the activity was minor, GNS only expected the island and areas directly surrounding it to be affected.