Waskita Sutadewa, spokesman for the disaster mitigation agency in Karangasem district around Mount Agung, said almost 11,300 villagers have been officially evacuated but admitted the real number of displaced might be two or three times that, since many have fled voluntarily.
It was the third time in little more than a week that the alert level had been raised.
The indonesian authorities declared on Friday a state of maximum alert on the tourist island of Bali, fearing the eruption of a dormant volcano for over 50 years, after earthquakes had driven thousands of people to flee.
Mount Agung, about 75 kilometers (47 miles) from the tourist hub of Kuta, has been rumbling since August and officials have recommended that people stay at least nine kilometres away from the crater. The spokesman of the national agency in charge of natural disasters, Sutopo Purwo Nugroho, was advised to stay calm and not give credence to the rumors.
Bali on alert amid fears Mount Agung volcano will erupt
Authorities warned tourists and residents to avoid camping or hiking within a 9 km (6 mile) radius of the crater as seismic tremors rattled some areas and smoke rose above one of the world's most popular tourist spots.
Nugroho said the current activity - there have been hundreds of tremors daily since Monday - resembled the behaviour in the run-up to that eruption.
The country of thousands of islands 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.
The "Ring of Fire" is where tectonic plates collide and move, causing nearly 90 per cent of the world's earthquakes.