"I'm not sure how big an area it is. We haven't evacuated anyone, but we're just keeping people away from the area. It's in scrub, it's not in an area where there are people.
"There's a lot of smoke and we've got the helicopter here at the moment pouring water on it," Mr Blackledge told NZPA.
Meanwhile, eight fire crews were battling a scrub fire near Cornwallis Beach, 31km south-west of Auckland, at the corner of Huia Rd and Pine Rd.
The fire broke out at 12.20pm and had spread over two hectares, but it was not close to any buildings.
"We haven't had to evacuate anyone as it's right in the bush," Mr Smith said.
A helicopter was on standby.
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