An ash cloud from a Chilean volcano has expanded to cover all of Tasmania and parts of southern Victoria overnight.

A large number of flights to and from Tasmania, Melbourne and New Zealand were cancelled, delayed or diverted to other locations by the airlines due to the ash cloud overnight.

Some airlines are resuming services today but significant flow-on delays are expected in the national air traffic network.

Airservices Australia, a government-owned corporation providing safe and environmentally sound air traffic management and related airside services to the aviation industry, said it is closely monitoring the ash cloud with the assistance of the Bureau of Meteorology’s Volcanic Ash Advisory Centre (VAAC).

It said the northern edge of the cloud now covers Tasmania and Melbourne and may reach the ACT by this afternoon. It is located at high altitude (between 20,000-35,000ft or around 6-10.5km).There has been no significant change in the overnight forecast.

“Airservices traffic management officers in our National Operations Centre are continuing to work with airlines to minimise disruptions wherever possible,” it said.

“Decisions on when and where flights will operate are made by individual airlines and operators. No airports have closed.

“Detailed information on the volcanic ash cloud is being provided to airports, airlines, CASA and Airservices by the Bureau of Meteorology. The airlines will make decisions on how flights operate based on a careful assessment of this information. CASA is monitoring the actions being taken by the airlines.

“Airservices air traffic management surveillance systems and air traffic control operations are unaffected by the ash cloud and we are providing full air traffic control services to all operating aircraft,” the company said.

Qantas cancels flights

Qantas has cancelled all scheduled flights to and from Melbourne, Tasmania, Auckland, Christchurch and Wellington until 10:00am on Monday 13 June as a result of volcanic ash from the Puyehue-Cordon Caulle volcano in Chile.

Qantas said it will continue to monitor the movement of the ash cloud and determine its impact on flight operations as the situation develops. A further update can be expected early on Monday 13 June.

“The Qantas Group's approach to flying is based on the highest standards of safety and risk assessment. Safety is always put before schedule,” the airline said.

Virgin Australia resumes flights

The Virgin Australia Group of Airlines will recommence services affected by the ash plume into and out of Melbourne; Tasmania; and New Zealand from 0700 today.

Group Executive Operations Sean Donohue said that the airline had been working closely with representatives from the Bureau of Meteorology and the Volcanic Ash Advisory Centre to confirm the safe resumption of services.

“Overnight we have been monitoring closely the situation and we now believe that conditions are safe to operate. We will be operating a full schedule today with minimal cancellations and our priority will be to get all Guests to their destination as safely and smoothly as possible.

“Guests holding a reservation for travel today should check the website first before leaving for the airport if they have not already been contacted by our Guest Contact Centre,” he said.

Passengers queue at the Virgin Blue check-in counter at Sydney's domestic airport after some flights were cancelled due to volcanic ash