Bali airport closed as volcano alert rises to 'highest level'

Bali's main airport has been closed after a volcano eruption alert was raised to its highest level.

People within 10km of Bali's Mt Agung have been told to immediately evacuate.

Ngurah Rai Airport is likely to remain closed for hours, as the ash cloud from the erupting volcano poses a threat to aircraft flying in the area.

There are genuine fears there could be an imminent major eruption, according to the country's National Board for Disaster Management.

Thousands of tourists have been left stranded amidst the increased alert, with flights cancelled as ash fills the sky.

"Continuous ash puffs are sometimes accompanied by explosive eruptions accompanied by a weak sound of boom which sounds up to 12km from the summit," the National Board for Disaster Management wrote in a Facebook post.

"The rays of fire are increasingly observed at night. This indicates the potential for a larger eruption is imminent.

"The dangers are dynamic and continuously evaluated, and can be changed at any time following the latest observation data.

"People within a radius of 10km are urged to immediately evacuate in an orderly and calm manner."

Agung rises majestically over eastern Bali at a height of just over 3000 metres. When it last erupted in 1963 it killed more than 1000 people and razed several villages.

The eruptions have sent a plume of volcanic ash and steam more than 6000 metres into the skies above the popular holiday island, sparking flight disruptions.

Newshub / Reuters