An air quality scientist says we should not worry about air pollution from the Australia bushfires.
On Sunday a large plume of smoke blanketed the upper North Island, turning the sky blood orange.
NIWA air quality scientist Guy Coulson says the smoke spread tiny particles, scattering light and changing the colour of the sky.
Despite the strange visual effect, though, the particles have not yet brought any health concerns.
"They haven't reached any values or concentrations that would trouble our regulations or standards," Dr Coulson told Newshub.
As a precaution, Dr Coulson advised that "people with asthma or respiratory problems stay indoors or avoid strenuous exercise - but I wouldn't expect that there'd be any particular health effects from this episode".
The eerie effect on Sunday prompted thousands of people to take to social media to question what was happening and share photos of the event.
Many people even called the police, checking if everything was okay.
The bushfires in Australia continue to rage across the country. More than 5.25 million acres of land has been burnt in the fire season so far, with almost 1500 homes destroyed in New South Wales alone.
At least 20 people have been killed.
Firefighters are under increasing pressure as conditions continue to worsen and there seems to end in sight.
On Sunday, New Zealand's Minister of Defence Ron Mark announced the Government would send support to Australia to help tackle the blazes.
That follows an announcement by Australia's Prime Minister Scott Morrison on Saturday that the country's Defence Force Reserves would also be deployed to the fire zones.