Fire crews will today head back to the scene of a large rubbish fire at a Waikato landfill.
Residents have had to keep their windows and doors shut since Sunday afternoon after a blaze broke out at the Hampton Downs landfill about 10am.
Fire and Emergency New Zealand (FENZ) asked those who live within 10km downwind of the landfill to avoid breathing in the smoke because of its possible toxicity due to the range of household waste products burning at the site.
Rural residents within that area who used roof water should stop collecting it immediately and clean their roof before collecting water again, the organisation said.
Three helicopters, four pump trucks and six tankers were at the scene at the peak of the blaze.
A northern communications spokesman today said landfill management stayed at the scene and kept an eye on the fire overnight.
In a post on its Facebook page, FENZ said it was not treating it as a hazardous substance fire.
It also confirmed he majority of the current cloud from the fire was steam and urged residents to keep downpipes to water tanks closed.
"The water currently in your tanks should be safe to drink. Rain is predicted for your area. 1-2 hours of solid rain will be enough to clean roofs and if no smoke/steam is near you, you can re-open down pipes."
Fire crews were called back about 2.30am for a short time, but would return at first light, about 7.30am, to ensure that it was completely extinguished.
A Waikato Regional Council spokeswoman said they had been told by landfill staff that the fire was contained to an area which received general household waste and demolition material.
"That means the smoke may be toxic due to the range of products burning at the site."
The fire was not in an area which received restricted asbestos material.
One local resident, who wanted to be known as Fiona, described the smoke as "acrid" and was worried about the effect on not only her own health but also the many animals she had at her property.
"It's horrid, have lost sense of smell as it is so acrid."
She'd hardly slept overnight and could see still the fire glowing overnight.
She said the smoke seemed more dense than what it was yesterday.