School holiday flights to Bali have been thrown into chaos by an eruption that has spewed volcanic ash up to 18 kilometres into the air and showered villages.

Low-cost carrier Jetstar has cancelled a number of services to the holiday island on Monday evening, while the pin has also been pulled on return trips to Australia.

WATCH THE VIDEO ABOVE: Volcanic ash causes chaos for Bali-bound school holiday flights.

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Qantas Group said it was monitoring the situation closely and that “safety is always our top priority”.

“We will contact customers directly if their flight is disrupted,” a spokesperson told 7NEWS.com.au in a statement.

Some Virgin services have also been cancelled.

7NEWS understands two AirAsia services from Perth will go ahead as scheduled on a different flight path.

“Some flights between Australia and Bali have been cancelled or postponed due to volcanic ash from Mount Lewotobi Laki-Laki,” Smartraveller said.

“If your flight is affected, contact your airline and insurance provider for alternative travel and accommodation arrangements.”

Indonesia’s Geology Agency said Mount Lewotobi Laki-Laki had unleashed a huge column of volcanic material that had showered some villages in grey and black ash.

Local residents reported strong booms, although there was no immediate report of casualties.

The country’s volcano monitoring agency had increased the volcano’s alert status to the highest level after an eruption on June 18, and more than doubled an exclusion zone to a 7km radius since then as eruptions became more frequent.

An eruption of Mount Lewotobi Laki Laki in November killed nine people and injured dozens. It also erupted in March.

The 1584-metre mountain is a twin volcano with Mount Lewotobi Perempuan in the district of Flores Timur.

Indonesia is an archipelago of 270 million people with frequent seismic activity.

It has 120 active volcanoes and sits along the “Ring of Fire”, a horseshoe-shaped series of seismic fault lines encircling the Pacific Basin.

- With AAP