Jetstar has cancelled all flights in and out of Christchurch, Queenstown and Wellington until midday tomorrow because of the Chilean volcanic ash cloud.
All other trans-Tasman and international services would operate as normal, the airline said.
Jetstar earlier cancelled all flights to and from Wellington, Christchurch and Queenstown today after a wind change pushed ash from Chile's Mt Puyehue Cordon Caulle volcano back over the country.
Air New Zealand flights were continuing to operate as normal, flying around the ash.
Jetstar said it would continue to monitor the ash cloud in conjunction with the Volcanic Ash Advisory Centre and the Bureau of Meteorology.
Jetstar yesterday dismissed suggestions it cancelled flights for financial reasons as "absurd".
Forsyth Barr aviation analyst Rob Mercer had said Australian airlines chose not to fly in and out of New Zealand during the past two weeks for financial reasons, not because of the safety risks posed by ash clouds.
Jetstar Group chief executive Bruce Buchanan rejected that, saying the airline was focused on safety alone.