Hazy conditions and a sulphury smell in the Bay of Plenty is being explained by a phenomenon called volcanic fog.
GeoNet said increases in gas emissions from Whakaari/White Island have combined with a developing sea fog in the Bay of Plenty to create a phenomenon known as "vog" or volcanic fog.
In a social media post, GeoNet said: "Vog is created when the sulphur-based volcanic gases mix with atmospheric moisture to form an aerosol.
"The light northerly winds are driving this onshore, there has not been an eruption to produce this.
"A vog can be unpleasant producing watery eyes and a stinging sensation. Those with respiratory health issues should be cautious. A vog can also reduce visibility, creating a hazard for road, air and ocean traffic, so please take care," GeoNet said.
Bay of Plenty residents, from Whakatāne, Kawerau through to Pāpāmoa have taken to social media to describe the sensation.
"The smell when I opened the door this morning, and man my nose hurt for a bit after. The smell was through the whole house. Even overpowered the diesel soak work uniform of the husbands in the garage," one said.
Others described a strange haze in the air and a sulphury smell.
"Just walked outside and didn't know what I was seeing? Is it rain is it smoke?"
"That explains why I was struggling to breathe," another post said.