Photographic evidence from Vanuatu's Ambae volcano confirms a volcanic cone island has risen from the bed of the Manaro Voui crater lake.
The cone is growing in height and size and the style of its activity has changed with more frequent explosions, volcanic ash and gas clouds.
Vanuatu's Geohazards Department said on Wednesday the alert level for the volcano remained at the second highest setting with activity likely to continue.
The Department said some explosions would appear more energetic to the local population on Ambae, who may feel air waves from the larger ones.
It warned people from Ambae and neighbouring islands might also continue to hear loud explosions, view volcanic ash and gas columns and see glowing over the mountain at night.
It said the current event was now becoming similar to the 1870 eruption with cone building in the summit caldera.
A restricted area of risk of three kilometers has been set up around the active vent.
The volcano became significantly more active on 22 September when the alert level was raised to level 4 leading to the mass evacuation of the islands' population.
The level dropped back down to level 3 on October 6 and most residents returned to contend with damaged crops and water supplies contaminated by ashfall.