Canberra, Jul 9 (IANS): Thousands of Australian holidaymakers, who had come upto Bali, have had their travel plans thrown into chaos, as the ash cloud from a volcanic eruption on the Indonesian island of Java continued to affect air services.

Low-cost carrier Jetstar was forced to cancel 12 flights over Wednesday and Thursday and is under pressure to get travellers home before the school holiday period ends on Friday, Xinhua reported.

Late on Wednesday evening, Jetstar released a statement that more services would be affected if the conditions did not improve.

"Jetstar will make an assessment of the flying conditions on Thursday and update customers should further cancellations be necessary," the airline said on its website.

"We regret the frustration these cancellations and delays will cause our customers, however, we will always put safety before schedule."

The airline said that travellers affected by the cancellations would be re-booked onto another flight within seven days, for no added charge.

Virgin Australia delayed four flights between Australia and Bali on Wednesday night by 12 hours. A spokesperson on Thursday confirmed that all flights leaving for Australia from Bali would depart on schedule despite uncertainty over conditions.

Mount Raung is located on the Indonesian island of Java, nearly 150 km from the Balinese city of Denpasar. It erupted last week causing widespread airport delays and cancellations for most major carriers.

The announcement from Jetstar follows nine cancellations last week, along with the cancellation of four Virgin Australia flights after Mount Raung first erupted.

Volcanic ash has the ability to contaminate fuel, water systems and can make engines flameout.