The island is located about 48km offshore from Whakatāne, in Bay of Plenty.
Earth Sciences NZ said an observation flight yesterday afternoon confirmed that activity at the island had moved from intermittent to passive eruption of a continuous steam and gas plume, which includes volcanic ash.
A blanket of volcanic ash could be seen around the active vent in the main crater, and a small amount was being carried upwards in a column of steam and gas.
The discharge was weak with no evidence that any explosive eruption had occurred, Earth Sciences NZ said.
The size and shape of the active vent was unchanged from its last observations on October 12, but some ash had accumulated close to the vent and was now thinly spread across the main crater floor and outer flanks of the island.
The temperature at the vent had increased from about 100C to about 395C since last week and sulphur dioxide gas from the volcano was also being detected daily by satellite.
While the current activity was quite passive and low energy, volcanic activity could escalate with little or no warning, Earth Sciences NZ said.
Twenty-two people died after an eruption happened as 47 tourists and their guides visited the island in December 2019.
Whakaari/White Island has remained closed to visitors since the tragedy.