Update: Volcanic ash cloud disrupts flights to Jakarta

Update: Jetstar has announced most flights will be returning to normal from Friday morning onwards. However, its Perth-Jakarta service may soon be affected by the volcano's ash cloud.

Previous: Flights to and from Australia are being hampered by the Mount Merapi volcano, with Qantas and Jetstar changing their schedules on flights to Jarkarta and Bali.

Jetstar flights into Bali will now only fly during daytime hours. A Jetstar spokesperson told AAP the airline will be taking a "safety-first approach" to night flights.

Qantas has cancelled a number of flights into Jakarta, affecting hundreds of passengers. This represents a reversal of last Sunday's decision, when Qantas said they would continue with flights into the region.

Though the constant eruptions from the volcano have become less frequent, concerns about ash are keeping airlines from flying. Also affected are Malaysia Air, Jetstar Asia's low-cost carrier Valuair and Hong Kong's Cathay Pacific. Cathay has stated it is expecting to resume flights today.

Previous: The continued eruption of Indonesia's Mount Merapi volcano has caused Singapore Airlines, Malaysian Airlines and Lufthansa to suspend flights to and from Jakarta.

Believed to be Mount Merapi's most powerful eruption in a century, the resultant clouds of ash are considered a risk for aircraft and their engines – similar to the effects of the Icelandic volcano which brought European air traffic to a standstill in April this year. Volcanic ash poses a threat to planes because the heat of jet engines can cause ash to become molten within the engine.

MAS expects the Jakarta route to be affected for at least two days.