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The airlines said meteorologists and the Volcanic Ash Advisory Centre had deemed it unsafe to fly around Denpasar Airport due to the eruption of nearby Mount Rinjani.
Both Virgin and Jetstar said they would make a decision on tomorrow's flights after receiving further expert advice.
"We continue to monitor the situation closely," Virgin said in a statement.
"The safety of our guests and crew is our highest priority, and we will keep customers updated as new information becomes available."
Jetstar said: "We will resume flying as soon as it is safe to do so and we will update customers if poor flying conditions lead to further cancellations."
Both airlines advised people currently in Bali not to travel to Denpasar Airport without a confirmed rebooked flight.
There are other options for travellers stranded in Bali. All other airlines are still operating because they have a different threshold for cancelling flights.
This is the second time in recent months that ash has affected Bali flights. Holidaymakers were stuck for up to a week in August following the eruption of Java's Mt Raung.