NZ, Adelaide flights grounded

"Over the course of this afternoon and later today hopefully we will have some advice on what we can do tomorrow."

Qantas spokesman Tom Woodward said safety was the highest priority and, while the airline regretted the inconvenience to travellers, the measures were critical to ensure the safety of passengers.

"Obviously the worst consequences (of the ash) getting into an aircraft engine is that flight safety is compromised because the engine fails or there is a range of other things that can result," he said.

Tiger Airways said its flights between Melbourne and Adelaide had been cancelled this morning, as had flights from Avalon Airport and Perth. About 7000 Tiger passengers have been affected, a spokeswoman said.

It comes as regional and international airlines continue to fly in and out of Adelaide this morning.

The airport’s website shows most flights are operating, including Virgin, Singapore Airlines, Rex, Sharp Airlines and Malaysia Airlines.

This afternoon, the airport’s website appeared to have crashed. Customers seeking to check flights online were met with the message: "An error occurred loading this web site".

Virgin Australia and New Zealand Airlines have chosen to fly under and around the volcanic plume, however Qantas spokeswoman Olivia Wirth said Qantas had a policy not to do that.

"The ash cloud is sitting over Tasmania at around 25,000 to 35,00 feet and that would require us to fly under or around," she told 3AW.

"At this stage due to the fact that we just don’t know enough about this ash plume, we’re not prepared to operate services under the ash cloud."

About 12,000 Qantas passengers are still affected by the cancellations, down from about 20,000 yesterday, she said.

Mr Wirth said the same number of Jetstar passengers were affected.

The volcanic cloud from the Puyehue volcano in Chile reached trans-Tasman airspace on Saturday night, and is expected to remain over the region for the next few days. The volcano began erupting spectacularly on June 4.

Meteorologists have warned further ash could return to Melbourne airspace tomorrow, however it is expected to remain clear for the rest of the day.

Meantime, traffic has eased on the Tullamarine Freeway after a flight backlog caused long delays this morning.

Cars were banked up about six kilometres along the freeway before 9am.

VicRoads road user services director Dean Zabrieszach said traffic had been unusually heavy.

He said cars were banked back to English Street near Essendon but traffic congestion has since cleared.

Melbourne Airport spokeswoman Anna Gillett urged passengers to leave early to reach the airport, where thousands of people are reportedly still waiting to board flights.

Qantas has warned it would take until the end of the week for scheduling to return to normal.

More than 66,000 domestic and international travellers’ flights have disrupted by the volcano, which meteorologists warned yesterday could cause more havoc with a second ash cloud drifting across south-eastern Australia.

Air New Zealand said it had not cancelled any flights, but its planes were flying at a lower altitude to avoid the plume.

Rob Walker from Airservices Australia said Adelaide was the main airport being affected by the ash today.

Mr Walker said another plume about 1200 kilometres in diameter and 4000 kilometres west of Perth was also being closely monitored but authorities hoped it would not make landfall.

Bureau of Meteorology forecaster Angeline Prasad said wind over the mainland was blowing parts of the plume over Adelaide.

Ms Prasad, based at the bureau’s Darwin’s Volcanic Ash Advisory Centre, said that although the ash was diffusing it was difficult to say when it would no longer be a hazard for aircraft.

The Civil Aviation Safety Authority said yesterday that it had no issue with airlines continuing operations provided they avoid the areas of forecast volcanic ash and any actual areas of ash.

With AAP