The eruption occurred at 9:43 a.m. local time, sending a column of thick white-to-grey ash up to 4,600 meters into the sky. The ash is drifting northwest of the mountain.
Planes were prohibited from flying at altitudes below 5 km around the volcano, which is located on Halmahera Island. An orange Volcano Observatory Notice for Aviation status has been issued.
Climbers and residents are strictly banned from climbing or engaging in any activities within a 3-km radius of the crater, Xinhua news agency reported.
Residents are also advised always to wear a face mask whenever ash dispersion occurs, as volcanic ash can spread at any time.
Mount Dukono, standing 1,087 meters above sea level, is one of Indonesia's 127 active volcanoes.