"From what [we] can tell smoke this thick has never crossed New Zealand from Australia in recorded history," Weather Watch said in a statement.

Forecaster Nava Fedaoff, from New Zealand's National Institute of Water and Atmospheric Research, said: "Everything was orangey-coloured. It was quite an incredible sight."

"People described it as ominous and apocalyptic; a lot of people were confused. It's definitely the talk of the town around here."

The haze shrouding the city triggered a flurry of calls to emergency services from alarmed residents and prompted Auckland's police to ask residents to keep the line clear for emergencies.

Smoky conditions - which Ms Fedaoff said were largely limited to "an optical impact" and did not greatly worsen air quality - eased on Monday as southerly winds swept the plume further north.

"We're not expecting anything like Sunday for the next few days. Maybe hazy sunrises and sunsets, but nothing dramatic."

The shifting smoke haze was moving towards an area south of New Caledonia and Fiji in the Pacific region. "It is possible it would impact some of those islands as well," Ms Fedaoff said.

Pyrocumulonimbus clouds in south-east Australia appeared to have produced a stratospheric smoke plume that continued to travel east across the Pacific toward South America, she said.

"Smoke that enters the lower stratosphere can linger for several months and so it is possible that it will encircle the southern hemisphere," she said.

Sunday's orange-tinted haze was not first time smoke from Australia's horrific bushfire season has reached New Zealand.

On January 1, smoke and dust from the fires stained skies sepia and turned snow-covered mountains caramel-coloured at the vast Tasman Glacier and Franz Josef Glacier on the country's South Island.

New Zealand Prime Minister Jacinda Ardern posted a photo on Instagram of the sun peeping through smoky skies as she said the country would send 22 firefighters to help battle the blazes.

"Even before we saw the smoke from fires across the ditch, I know we were already thinking of our friends and neighbours in Australia," she wrote.

"It’s been devastating to watch from afar, I can only imagine what it feels like to experience it directly."

Nearly 6 million hectares of bushland have burnt in Australia this bushfire season, with more than 100 blazes burning across NSW and Victoria on Monday.

Twenty-four people have died in fires across the country in recent weeks, including three firefighters in NSW.

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Smoke has covered fire-affected parts of Australia's east coast, choking regional areas as well as densely populated parts of Sydney and the ACT, to varying degrees since large and dangerous fires began burning in November.

In Canberra, federal government departments, universities and institutions including the National Gallery of Australia shut their doors this week due to acrid smoke blanketing the capital.

The city has recorded the worst air quality reading of any major city in the world multiple days this year.

Sydney residents breathed through 38 days of very poor air quality from November to mid-December, including 28 days considered to have been hazardous.