Transport ministry spokesman J A Barata said Ngurah Rai airport would be closed for several hours from midday (0930 IST) due to ash drifting from Mount Raung, on Indonesia's main Java island.
Australian carriers Jetstar and Virgin Australia announced they were canceling flights in and out of Bali today, a popular holiday destination that attracts millions of tourists from around the world every year.
The closure was the fourth shutdown of Bali airport in recent weeks due to the volcano, which has been spewing ash and lava high into the air since late June.
The most serious period was between July 9 and 12, when two closures forced almost 900 flights to be canceled or delayed and created a backlog that took days to clear.
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Indonesian government vulcanologist Gede Suantika told AFP that the volcano was today shooting out ash clouds that were larger than those it had recently been emitting.
"The volcano normally shoots out ash 700 to 800 metres but it's around 1,000 metres today," he said.
Air traffic is regularly disrupted by volcanic eruptions in Indonesia, which sits on a belt of seismic activity running around the basin of the Pacific Ocean and is home to the highest number of active volcanoes in the world, around 130.