Mount Agung has erupted for the second time in a week, prompting dears on Bali that a more serious eruption is imminent.

Flights have been disrupted over Bali after Mount Agung erupted on Saturday evening and three times early Sunday, sending ash 4,000 metres into the atmosphere. With prevailing (wet season) winds sending the plume over Lombok, the neighbouring island's main International airport has been closed, while Denpasar Airport remains open at this time.

An exclusion zone extending up to 7.5km from the crater remains in place, following the evacuation of more than 185,000 people after an eruption in September, and authorities have warned anyone remaining within it to leave the area. About 25,000 to 30,000 people are reportedly still unable to return home.

Airlines including Virgin Australia, Qantas, KLM and Jetstar were affected although many either continued their services or resumed them after a pause. Travellers were advised to check with their carrier.