More than 75,000 people were evacuated over the past few days as Agung has experienced hundreds of internal volcanic earthquakes.
According to the national volcanology center more than 560 volcanic tremors were detected on Sept 25.
Sutopo said it was "natural" people outside the immediate danger zone are leaving.
Although it's not possible to predict exactly when a volcanic eruption will take place, increased temblors in and around the mountain indicate that magma is building up and stirring inside the volcano. The volcano is now on the highest alert level and an exclusion zone of nine kilometers as been set from the crater. "Although alert level 4 (the maximum) has been declared since September 22, there is no guarantee that the volcano will erupt", an official from the National Disaster Mitigation Agency said. "Volcanoes are a stochastic system, many complexities are unknown by the human brain and technology". "The earthquakes are happening less frequently but the magnitude is getting stronger", Gede Suantika, a senior volcanologist at the agency told AFP.
"While the government will continue to try to minimize the economic losses of the community, the most important priority is the safety of the people here", Widodo told reporters. "The only records that we have is of the phenomena that were observed and reported by people around the volcano prior to the 1963 eruption".
If there's an eruption it could force the closure of Bali's worldwide airport.
In the event of an eruption and ash clouds that could disrupt air travel, authorities have made preparations for flights to be diverted to seven regional airports, including on Java and Lombok islands.
Authorities have been watching the volcano closely, and have so far urged tens of thousands of residents to flee the area with warnings of an "imminent" eruption.
Mount Agung is one of more than 120 active volcanoes extending the length of Indonesia, which straddles the Pacific Ring of Fire.