Most trans-Tasman and domestic airline services are expected to be operating as normal tonight as ash cloud from a Chilean volcano moves away.
Jetstar said today some flights were cancelled or delayed this morning because the ash had not dispersed as the Volcanic Ash Advisory Centre initially predicted.
However, domestic and trans-Tasman flights from Auckland, Wellington and Queenstown were operating from midday, it said.
Flights to and from Christchurch were expected to resume from 6pm, and some rescheduled flights would depart after that time. The airline had put on extra flights between Auckland, Sydney and Melbourne.
All its Australian domestic services were operating today, Jetstar said.
The airline would continue to monitor the situation.
Air New Zealand resumed all its domestic and trans-Tasman flights today, with flights in and out of Queenstown operating from 12pm.
A Qantas spokeswoman said trans-Tasman flights had resumed apart from one from Auckland to Sydney, one from Auckland to Brisbane and one from Wellington to Sydney.
All Qantas trans-Tasman flights have been suspended since Sunday.
Virgin Australia Group of Airlines spokesman Colin Lippiatt said the group's Pacific Blue trans-Tasman services had resumed today apart from four cancelled flights: two between Brisbane and Dunedin, one from Wellington to Brisbane and one from Christchurch to Sydney.
"Our latest information is that the ash cloud is moving away...and as it moves away there's less impact on services," he said.
Puyehue-Cordon Caulle began erupting on June 4 and volcanologists say its size and history indicate it could remain volatile for weeks.
Chile's National Service of Geology and Mining director flew over the volcano this week and told local newspapers it showed similar signs of activity to an eruption in 1960, which lasted for two months.
GNS Science volcanic geologist Graham Leonard, who is analysing the data, said there was no guarantee of how long the ash plumes would last.
"But the overall character of this volcano -- its personality -- is capable of producing drawn-out eruptions.
"Nobody is forecasting an immediate stop to any activity. Just the fact that it is a large, pyroclastic [explosive] eruption -- these things are typically capable of going on for at least weeks, if not months."
MetService, which had been providing the ash forecast on behalf of the Civil Aviation Authority to airlines, will monitor the situation as long as there is detectable ash.