The big dust cloud that has been causing visibility and air quality problems in parts of Australia is expected to arrive in New Zealand today.
MetService said it would be blown across the South Island and may affect parts of the central North Island on Friday.
A large dust storm swept parts of New South Wales and Canberra this week as a cold front pushed strong winds ahead of it across the south east of the country. The storm brought wind damage and power cuts in the Canberra area, and thick dust was moving into southern Queensland.
The west coast of the South Island is forecast to be affected by some of this dust from this morning through until tonight, and western parts of the North Island tonight and into Friday morning.
Duty forecaster Heath Gullery said it would most likely cause redness in the sky at dusk and dawn.
"It's most likely to be seen as an extra redness in the sky during sunrise and sunset. There may be an extra bit of haziness in the sky," he said.
He said it was a fairly rare event likely caused by dust and smoke from fires in Australia. Most of the dust will be in the upper atmosphere.
MetService forecasters were not sure about the density and amount of dust that would eventually reach New Zealand but expected the cold front to make landfall over Fiordland this morning.