A cloud of ash from a volcano in southern Chile has forced Qantas to cancel some flights on Sunday between New Zealand and Sydney.
The Puyehue-Cordon Caulle volcano began erupting on 4 June.
The head of the Australian Bureau of Meteorology's Volcanic Ash Advisory Centre in Darwin, Andrew Tupper, says strong winds had carried the main part of the cloud towards New Zealand.
He says it's expecting all of New Zealand to be covered by the cloud.
Qantas has confirmed it has cancelled several flights scheduled for Sunday including Flights QF45, from Sydney to Christchurch, QF46 Christchurch to Sydney, QF121 Sydney to Queenstown and QF122 Queenstown to Sydney.
The Civil Aviation Authority says it is up to airlines to alter routes and flying altitudes.
Air New Zealand says it does not expect flight delays or cancellations, but expects to be able to adjust routes and altitudes to stay clear of the ash.
The CAA says ash particles are expected to arrive over the South Island and the plumes are likely to be between 20,000 and 30,000 feet - the cruising level for most jets.
CAA spokesperson Bill Sommer says airlines may have to alter flight altitudes or routes to ensure travel is not disrupted.
Mr Sommer says the situation is being monitored by the MetService which operates the Volcanic Ash Advisory Centre in Wellington and provides information to airlines and the CAA.
An ash cloud from the eruption is continuing to cause travel chaos in parts of Argentina and Uruguay and has also affected flights in the south of Brazil.