Homes and a caravan park were evacuated overnight as high winds fanned a large vegetation fire near Canterbury's West Melton.
About 50 firefighters had been tackling the blaze overnight, and four helicopters would be on scene with monsoon buckets at first light Monday.
Fire and Emergency NZ said the blaze was first reported about 9pm Sunday.
By 10pm, the fire was "approximately 1km x 1km, with high winds in the area".
At 3am, 12 trucks, tankers and support vehicles were at the scene.
A caravan park, in The Willows area, had been evacuated, Fire and Emergency NZ said.
The area east of Thompsons Road to McKays Road was also evacuated around midnight. Evacuees were sent to the West Melton Community Centre.
In an update at 4:30am, Fire and Emergency NZ said residents could now return home, "but must be ready to leave again if required".
"We will have a significant presence in the area this morning so please continue to avoid the area."
Smoke could be smelled from up to 30km away.
The fire was described as "uncontained", and FENZ said it would have "a better and more accurate picture of the fire's size" once day broke on Monday.
The blaze came just days after a huge fire broke out in the Bridge Hill area, leading to school camps and part of a village being evacuated.
That fire, which had since grown to about 1000 hectares, was expected to take a week to fully extinguish.
A third Canterbury fire, at Kirwee, was brought under control on Sunday afternoon.
Firefighters had used heavy machinery to build a fire break and remained on site on Sunday night in case of any flare-ups.
"Firefighters will return tomorrow to continue working on the deep-seated hotspots."
Meanwhile, crews in Auckland put out a large vegetation fire in East Tamaki on Sunday night.
Fire and Emergency said crews were called to a fire near the roundabout on Highbrook Drive just after 9pm.
Three fire trucks and a water tanker battled the blaze, which had been put out by 10.20pm.
The crews had left the scene after dampening down remaining hot spots, a spokesperson said.
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