SYDNEY - Australian airlines continued to cancel flights to Bali for a third day on Friday over a volcanic ash cloud, despite other airlines still operating flights to the Indonesian island.

Australian tourists are becoming increasingly frustrated with the flight cancellations by Qantas Airways' low cost subsidiary Jetstar and rival Virgin Australia, as they continued to monitor the volcanic ash cloud over Denpasar airport, Xinhua news agency reported.

Indonesian carrier Garuda, Air Asia, Singapore Airlines and other airlines flying out of Bali have not cancelled flights, said the news agency.

"They rely on their own judgment," Bali tourism chief Ida Bagus Ngurah Wijaya said on Thursday.

Flights to and from Bali, one of Australia's most popular holiday destinations, have been disrupted since July 3, as ash from Mount Raung volcano on the island of Java, 150 km west of Denpasar, drifted intermittently towards the airport.

In a worst case scenario, volcanic ash can shut down a plane engine. In a best case scenario, volcanic ash can do damage to vital systems and the airframe when planes come into contact with ash clouds, said Xinhua.

Indonesia AirAsia advised that its flights have been re-routed away from the affected areas, but it is keeping a close eye on any updates from relevant scientific agencies.

Jetstar and Virgin Australia said they would continually monitor the situation and advise affected passengers accordingly.

Both carriers said they would also look at having additional services in and out of Bali over the coming days if conditions improve.