First White Island eruption in three years
The Bay of Plenty's volcanic White Island has erupted, depositing ash on the island's crater floor.
GeoNet volcanologist Agnes Mazot said the minor eruption happened between 9.30 and 11pm on Wednesday night.
By 11pm the seismic activity had returned to normal.
Mazot said this was the first time the volcano had blown since 2013.
GeoNet scientists had noticed a reduction in water levels of the volcano's crater lake during the past couple of weeks so they were aware something was going on.
However, these type of eruptions were unpredictable, she said.
Tourists and helicopter companies who travelled to the popular destination on Wednesday were all safe and accounted for.
Mazot said they were "watching closely" for any further activity but it was difficult to know when an eruption was brewing.
"It can change at any time."
The aviation code for those flying in the area was changed to orange, meaning the volcano is exhibiting heightened unrest with increased likelihood of eruption.
While the volcanic alert level had been raised to 3, which meant there was a minor volcanic eruption.
Meanwhile, Waikato Civil Defence posted a light-hearted warning on its Facebook page.
"There's been a bit of excitement on White Island!
"A minor eruption last night...normally White Island does lady volcano farts (or "Windy Pops"), but last night she did a ripper loud one!"
Waikato Civil Defence said GeoNet scientists were "keeping a close eye on her 'windy pops'" and would let everyone know if they looked like they were going to get "raucous".