Dozens of flights in Australasia have been grounded as an ash cloud from South America drifts over the Atlantic and Indian oceans.

Originating in Chile, the cloud has drifted around the world to lie over southern parts of New Zealand and Australia.

Heavily hit is Australian carrier Qantas Airways, which has been forced to cancel 56 flights.

These include all operations out of Melbourne and the New Zealand hub of Auckland.

“Qantas will continue to monitor the movement of the ash cloud and its impact on further operations,” read a statement.

Air New Zealand had earlier said it was flying at lower altitudes and altering flight paths to avoid the ash, and did not anticipate any disruption.

Fine particles of ash, which pose a danger to aircraft bodies and engines, were carried east by the prevailing winds to sit between 20,000 and 35,000 feet across southern parts of Australia and New Zealand.