There have been no fatalities or injuries from the eruption, as yet, according to Indonesia's Volcanology and Geological Hazard Mitigation Centre.
People have been advised to stay at least three miles from the crater's mouth and should be aware of the peril of lava, the agency said.
The volcano had been dormant for over 400 years until an eruption in 2010 in which two people were killed. Since then several eruptions have occurred.
An eruption in 2014 killed 16 people, while seven died in a 2016 eruption.
The cone-shaped Mount Sinabung stands at 2,460 metres high and is among more than 120 active volcanoes in Indonesia.
The region is prone to seismic upheaval due to its location on the Pacific “Ring of Fire”, an enormous network of volcanoes and fault lines encircling the Pacific Basin.
It's noon in Indonesia, that's the ash from Sinabung volcano blocking the sunlight. pic.twitter.com/HlDrFzmeUb— Manuel Ruiz (@mozzaic_)August 10, 2020
Due to the renewed activity of the volcano over the last decade, some 30,000 people have been forced to leave their homes around the mountain.
Additional reporting by PA.