A view of the Mount Agung volcano erupting, in Karangasem, Bali island, Indonesia. Picture: AP Photo/Firdia Lisnawati

Jakarta - Indonesia's disaster mitigation agency said 40 000 people had been evacuated from near Bali's erupting Mount Agung volcano, but tens of thousands still needed to move with an imminent large eruption warning issued on Monday.

"We really ask people in the danger zone to evacuate immediately because there's a potential for a bigger eruption," said Sutopo, a spokesperson for Indonesia's disaster mitigation agency (BNPB).

Read more: LOOK: Volcano covers Bali resorts in ash

He told a briefing that 40 000 people had evacuated out of around 90 000-100 000 residents estimated in the 8-10 km (5-6 miles) exclusion zone around Agung.

"Not all residents have evacuated yet. There are those (who haven't evacuated) because their farm animals haven't been evacuated yet. There are those who feel they are safe," he said, adding that security personnel were trying to persuade people to leave but they could be evacuated by force.