New Zealand's geological agency GNS Science said on Saturday that it's raised the alert level for White Island after the volcano erupted.

The agency said a moderate explosion eruption, lasting about a minute, happened just after 8 p.m. Friday night.

GNS Science said the volcanic alert level has been raised from one to two which indicates minor activity.

The aviation color code has been upgraded to orange, the second- highest alert level.

GNS volcanologist Arthur Jolly said the eruption was about the same size as the previous one in August 2012, Radio New Zealand reported.

Jolly said the eruption threw mostly mud, rather than ash, into the air.

He said bad weather on Saturday prevented GNS volcanologists from flying over the island to observe the volcano.