An eruption at White Island overnight has seen the volcano's alert level raised.

GNS duty volcanologist Agnes Mazot says the eruption at White Island happened sometime between 9.30pm and 11pm.

White Island's volcanic activity has increased. Image: GeoNet.

'As a consequence of this activity the Volcanic Alert Level is now raised to Level 3 (Minor Volcanic Eruption) and the Aviation Colour Code to orange.

'No eruptive activity has been seen since about 11pm.”

Agnes says yesterday's eruption was accompanied by a moderately elevated seismic activity.

'The seismic activity is now back to normal.

'The eruption appears to have deposited material over north side of the crater floor and up onto north crater wall,” says Agnes. 'There is not yet a clear view of crater area visible from cameras.”

GNS Science volcanologists are monitoring the volcano and further information will be released as soon as it is available.