Flights from Sydney to Jakarta have been delayed because of a volcanic ash cloud in Java.
A Qantas spokeswoman said the flight paths from Australia to Singapore had been altered because of the billowing plumes coming from Mount Kelud.
Mount Kelud is considered one of the most dangerous volcanoes on the main island of Java. Television footage showed it releasing red-hot ash and rocks high into the air late Thursday night just hours after its alert status was raised.
The QF41 Sydney to Jakarta was due to depart at 2.25pm on Friday but is currently listed as rescheduled to leave at 10am on Saturday.
The QF 42 Jakarta to Sydney was due to depart at 7.45pm on Friday but has been rescheduled to depart at the same time on Saturday.
Qantas is monitoring the situation.
A Virgin Australia spokeswoman said the airline had cancelled all Phuket, Denpasar, Christmas Island and Cocos Island flights and was reassessing the situation on Saturday.
The statement said its meteorologists were continually monitoring the weather situation, in consultation with the Volcanic Ash Advisory Centre in Darwin.
"We will recommence normal operations as soon as the volcanic ash cloud safely allows it," the Virgin statement said.
International humanitarian agency World Vision Indonesia director of humanitarian and emergency affairs Bill Sumuan said that Mount Kelud showered volcanic ash and gravel 30 kilometres from its crater. Residents within 10 kilometres to evacuate.
“Local authorities have urged about 200,000 people to evacuate,” Mr Sumuan said.
“People used their motorcycles, cars and trucks to flee their villages as volcanic ash limited visibility to just metres,” he said.
Three international airports – Jogyakarta, Solo and Surabaya – have been forced to close in the reduced visibility from the eruption, he said. The closures could hamper the delivery of aid if needed.
Mr Sumuan said there were no immediate reports of casualties or damage to properties so far. He said the eruption had triggered strong explosions and tremors could be heard and felt as far as 50 kilometres away.
World Vision Australia's Emergency Preparedness Fund is accepting donations. worldvision.com.au/emergencies