The Civil Aviation Authority (CAA) says the ash cloud from a volcanic eruption in Chile is likely to disrupt flights in New Zealand throughout the weekend.
The cloud has dropped slightly to 18,000 feet due to weather conditions.
Qantas and Jetstar have cancelled all flights in and out of New Zealand for another full day due to the volcanic ash cloud from Chile.
The airlines say their aircraft will not fly on Saturday.
Pacific Blue has also cancelled all flights in and out of New Zealand, with some cancellations already listed for Sunday.
Air New Zealand says it is keeping an eye on the weather and the ash cloud but at this stage intends to keep flying below the cloud.
CAA meteorological manager Peter Lechner says the cloud on Friday stretched from just below Tasmania to Antarctica.
He says the cloud is expected to stay over New Zealand skies for at least the next two days but could be here for longer if the weather doesn't improve.
Mr Lechner says airlines' ability to fly will depend on the height of the ash cloud. He says it's up to airlines to determine their safe flying level - which is usually based on their normal flying heights which range from 20,000 - 30,000 feet.
He says if they adjust flight paths they must meet CAA guidelines, which state that aircraft are not allowed to fly through ash clouds, or on flight paths that aren't already established.
The volcano in Chile is still erupting to a level of about 15,000 feet, but every now and then it sends a plume of ash to a height of 30,000 feet, he says.