Mount Sinabung on the Indonesian island of Sumatra has shot billowing columns of ash more than five kilometres into the atmosphere and hot clouds down its slopes.
The National Disaster Mitigation Agency said there were no fatalities or injuries from the eruption on Monday (local time).
The regional volcanic ash advisory centre in Darwin issued a “red notice” to airlines.
The volcano, one of three currently erupting in Indonesia, was dormant for four centuries before exploding in 2010, killing two people.
Another eruption, in 2014, killed 16 people, while seven died in a 2016 eruption.
Disaster agency spokesman Sutopo Purwo Nugroho said hot ash clouds travelled as far as 4.9 kilometres south.
About 30,000 people have been forced to leave homes around the mountain in the past few years.
Mount Sinabung is among more than 120 active volcanoes in Indonesia and is prone to seismic upheaval due to its location on the Pacific “Ring of Fire” – an arc of volcanoes and fault lines encircling the Pacific Basin.
— Bureau of Meteorology, Australia (@BOM_au) February 19, 2018
Meanwhile, more than 400 flights were cancelled in November after Bali’s main airport was closed amid warnings of a potential volcanic eruption at Mount Agung.
Mount Agung had been hurling clouds of white and grey ash about three kilometres into the atmosphere, prompting the evacuation of about 150,000 people.
It was estimated the threat of the eruption cost the island $1.5 billion in cancellations.