Auckland's sky turned eerie shades of yellow and orange on Sunday as a huge layer of smoke from the Australian bushfires cloaked swathes of New Zealand.

The haze was so bad that a "high number" of worried Aucklanders had rung 111 to alert police. Police issued a statement asking people to keep the line clear for emergencies only.

RICKY WILSON/STUFF A thick haze hung over central Auckland on Sunday afternoon.

At 5pm - four hours before the sun was due to set - the city was abnormally dark, with motorists using their headlights and street lamps turning on early.

The "unprecedented plume of smoke" from the west had turned upper North Island skies orange and the next main plume would thicken over Sunday afternoon, WeatherWatch said.

RICKY WILSON/STUFF Weather expert Philip Duncan described the smoke plume as a historic event.

The phenomenon could reduce temperatures as much as 4 to 5 degrees Celsius, WeatherWatch​ head forecaster Philip Duncan said, as he watched an even heavier plume approaching West Auckland in the mid-afternoon.

SUPPLIED Auckland's sky turned orange as the Australian bushfires smoke rolled in.

Duncan said based on available evidence and after chatting people in their 80s and 90s, Sunday's skies were ones "for the history books" and definitely linked to the vast Australian fires.

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Stuff readers across west, central, east and south Auckland and Waiheke Island have reported the unusual skies coloured yellow, orange and ginger.

RICKY WILSON/STUFF The otherworldly skies were visible at the ASB Tennis Arena on Sunday afternoon.

Smoke was filtering and blocking sunlight, and the skies were extremely gloomy because the smoke layer was sitting on top of cloud, Duncan said.

But he said even if it was a sunny day, the smoke layer was so thick, the skies would still be "very gloomy, very weird".

ANDREW BEACH Smoke from across the Tasman turned the skies in central Auckland a strange colour on Sunday.

Some readers have reported smelling smoke, and asked if that was possibly related to the smoke which westerlies were driving across the Tasman.

JACKIE ZIEGLER The yellow sky was also noticed on Auckland's North Shore.

Duncan said several people in the South Island reported smelling smoke late last week, when remnants of the Australian fires stained glaciers.

JOHN WEEKES The new bizarre yellow and orange skies in Auckland and elsewhere in the upper North Island were a product of the massive Australian bushfires.

"Those with asthma and breathing difficulties have noticed more difficulty breathing," Duncan added.

himawari8.nict.go.jp Satellite footage from Himawari-8 shows a new wave of smoke from the Australian bushfires drifting across the Tasman towards NZ.

MetService meteorologist Tahlia Crabtree​ said an upper level jet of westerly winds was driving the smoke across the Tasman Sea towards New Zealand.

Smoke from the Australian bushfires is making haste across the Tasman, driven by an upper level jet of westerly winds. Haze looks likely colour the skies of the North Island, and parts of the South Island later today. ^Tahlia pic.twitter.com/i7Wb1S4Ejn — MetService (@MetService) January 4, 2020

The smoke was likely to be seen across the whole of the North Island, Nelson, Marlborough, possibly Buller and North Canterbury.

HIMAWARI 8 SATELLITE Bushfire smoke approaches NZ at 11.50am on Sunday.

The concentration was expected to be similar to that which covered the South Island earlier this week.

Crabtree said MetService would be watching the satellite imagery throughout the day to monitor any changes.

GEORGE EMPSOM/SUPPLIED Smoke from bush fires in Australia turns the sun red above the Tekapo area on New Year's Day.

It was possible people would be able to smell and taste the smoke, but because it was not hanging around for long it was unlikely to have any long-lasting health effects, she said.

Much of the South Island awoke to sepia skies on New Year's Day, before the smoke spread to the North Island.

BRETT HEMMINGS The sky turns red over the New South Wales town of Bodalla. Westerly winds are sending smoke from the fires across the Tasman.

The smoke particles filter out the blue light in the spectrum and can make the sky look orange and the sun look red, particularly at sunrise and sunset.

More than 20 people have died in fires across Australia this fire season, with more missing in New South Wales and Victoria.

Rey (via Twitter) Snow near Franz Josef glacier turned brown earlier this week as a result of smoke from the Australian bush fires.

Across the Tasman, more than 1300 homes have been destroyed along with hundreds of thousands of hectares of bushland.