MetService meteorologists reported that no volcanic ash was detected in the plumes observed using satellite imagery.
While the event appeared to be brief, the island remained under close watch.
The volcanic alert will stay at level 3 for at least 48 hours while the Earth Sciences NZ Volcano Monitoring Group reassesses the situation.
The alert system is a scale of zero to six levels, with level 3 indicating a minor volcanic eruption.
There were currently no sensors installed on the island, and scientists relied on remote cameras, satellite data, periodic observation and gas measurement flights to track any developments, Mazot said.
Earth Sciences NZ would provide updates as new information became available.
Whakaari, 48km off the North Island coast, is one of New Zealand’s most active volcanoes.
The last previous eruption activity was observed on August 28, coating the island in a thin covering of ash. The activity settled quickly.
Today’s eruption came amid an ongoing inquest into the deadly eruption on December 9, 2019, which killed 22 people.