Qantas and its subsidiary Jetstar have cancelled all flights to and from Christchurch, Queenstown and Wellington until at least midday on Friday, due to continuing problems with the volcanic ash cloud from Chile.
A sudden wind change caused the cloud to move back over New Zealand on Wednesday after a two-day respite.
Jetstar says it is closely monitoring the ash cloud in conjunction with the Volcanic Ash Advisory Centre and the Bureau of Meteorology in Australia.
While Jetstar's cancellations currently go up to midday on Friday, Qantas has cancelled flights out of Queenstown until further notice and out of Wellington and Christchurch until 3pm on Friday.
Air New Zealand and smaller airlines such as Sounds Air are still flying as scheduled.
Pacific Blue is flying its normal trans-Tasman flights.
Civil Aviation Authority meteorologist Peter Lechner says the ash cloud should move off the east of the North Island by the weekend and is not likely to reach Auckland, a main gateway.