The Department of Meteorology and Geohazards in Vanuatu says it has upgraded the danger level of the volcano on Mr Yasur due to more explosions and ash eruptions.
The volcano on Tanna Island has been placed on alert level two, following an increase of activity recorded since last week.
A geophysical engineer at the Department, Sylvain Todman, says local communities are being warned to cover their water tanks and to be aware that ash could spoil gardens and fragile vegetables.
"It means more explosions, an increase of explosivity, more ash falling down to the close village and a lot of ash and some (volcanic) bombs falling down to the parking area and where the tourists used to witness the activity of the Yasur volcano."
Sylvain Todman says the Department of Meteorology and Geohazards is closely monitoring the activity and will prepare a response plan if the volcano increases to alert level three.