Sydney: Thousands of passengers were grounded Tuesday as the Chilean ash cloud returned to Australia with a vengeance, with hundreds of flights cancelled to Adelaide, Canberra, Melbourne and Sydney.
The cloud, created by the eruption of the Puyehue volcano high in the Andes more than two weeks ago, has looped the globe and made its way back Down Under to wreak fresh havoc.
State broadcaster ABC said more than 120,000 people had their travel plans thrown into disarray.
"The ash cloud is denser and larger than that which caused widespread disruption to flights last week," said Airservices Australia, adding that the plume was hovering between 20,000 and 40,000 feet (6-13 kilometres).
"It is also predicted to linger longer over southeast Australia. It is spread in a large band below the Australian continent and is predicted to continue to move to the northeast and east in coming days."
Qantas suspended services to and from the South Australian capital Adelaide as well as Canberra and Sydney -- Australia`s busiest airport.
Its discount airline Jetstar also called off Adelaide and Sydney flights while Tiger Airways grounded its entire fleet, with no services anywhere.
Virgin, meanwhile, suspended flights to Adelaide and Canberra, with routes to major hubs Sydney and Melbourne as well as Tasmania not flying from 4:00pm (0600 GMT), with the disruptions expected to spill into Wednesday.
"Volcanic ash from the eruption of Mount Puyehue Cordon Caulle volcano in Chile continues to cause flight disruptions to the Qantas network," Qantas said.
"At Qantas safety is our first priority and a number of flights have been cancelled or re-routed to avoid the volcanic ash cloud."
Its morning services from Sydney to Bangkok, London, Singapore and Frankfurt were not affected, but international flights later in the day were hit.
Some services, including from Singapore and Johannesburg, were diverted to Brisbane, while its Hong Kong and Los Angeles flights have been delayed.
A spokesman said announcements would be made later on other international routes, including its evening services to London and other parts of Europe.
Meteorologists said that while the ash had thinned during its travels around the world it was still clearly visible on satellite images and was moving at an altitude where aircraft generally cruise.
"It is the same cloud that has gone right around the world. It is still dense and it is still hazardous to aviation," a spokesman at the Darwin Volcanic Ash Advisory Centre.
The cloud first entered Australian and New Zealand airspace just over a week ago, causing some airlines to ground all flights to affected areas while others chose to divert their planes under and around the plume.
The Volcanic Ash Advisory Centre`s director Andrew Tupper said the plume was a rare occurrence and a third loop back to Australia was not likely.
"A third time round would be unprecedented," he said, adding that it was a testing time for airlines.
"It is a very complex problem for the airlines to manage. Obviously they have to take a conservative approach."
Ash poses a significant threat to aircraft because once sucked into engines it can be converted into molten glass as a result of the high temperatures and potentially cause an engine to fail.