The alert level was maintained at its highest after Semeru on Java island erupted 10 times on Wednesday, emitting massive plumes of ash and sending lava and rocks as far as 13km down its slopes, officials said.
The climbers were stuck overnight at a lakeside camping area at the foot of the volcano about 6.4km from the crater but were now being helped to safety, said Septi Wardhani, an official at Semeru national park.
"All climbers with their guides are safe," Wardhani told Reuters. "The situation is under control,"
Footage from Indonesia's volcanology agency showed a huge cloud of hot ash billowing from the crater and blanketing the slopes of the volcano. Its last major eruption was in December 2021, when at least 51 people were killed and nearby villages were blanketed in ash.
Jetstar and Qantas said no flights from Australia to Bali had been impacted but the airlines were monitoring the situation.
The 3676m high Mount Semeru is one of about 130 active volcanoes in Indonesia, which straddles the Pacific Ring of Fire, a highly seismically active zone, where different plates on the earth's crust meet and create a large number of earthquakes and volcanoes.
East Java's rescue agency deployed dozens of personnel to assist the evacuation, with 956 people living close to the volcano already moved to schools, mosques and government buildings, said agency official Prahista Dian.
"We've also deployed personnel to search for whether there are still residents trapped or not," he added.
with AP and AAP
