Homes are being threatened and residents evacuated as a reignited scrub fire continues to burn on Great Barrier Island.
Firefighters were called to the Kaitoke beach area on the southern side of the island about 1.20pm.
Three helicopters with monsoon buckets and about forty firefighters are fighting the blaze.
Some businesses and homes under threat from the "substantial fire'' have been evacuated as a precautionary measure, said Great Barrier Community Board chairman Paul Downie, who described the fire as devastating.
"It's pretty gutting,'' he said.
He advised residents to prepare a bag of necessary items such as their driving licence and credit cards in case more people buildings needed to be evacuated quickly.
"I don't think we're at that stage yet, but we know Great Barrier is covered in a lot of flammable foliage.''
There were concerns about a number of buildings that could be in the path of the flames. Fire crews from the local station and several volunteers were working hard along with helicopters to contain the fire and prevent it from spreading, he said.
Claris Airport closed about 3pm and there were no inbound flights, said the operations manager, who gave his name as 'Greeney'.
Standing outside the airport, he could see flames, which were threatening to burn nearby manuka, pohutakawa and gorse.
"It's just across the runway. The (helicopter) buckets are struggling to keep it under control.
"We've got an onshore wind. It's heading towards the rubbish tip, golf course commercial buildings and a few houses,'' he said.
Departing passengers were being bused to the alternative Okiwi airstrip on the island.
The manager of the Crossroads Backpackers Lodge in Claris, Katie Langford, said they were getting ready to leave if the fire got too close.
"All I can see is quite a lot of smoke and we've got choppers buzzing around the place. It's still burning.
"We haven't been evacuated yet but we're just on standby,'' she said.
About 30 firefighters worked on Sunday evening to extinguish a vegetation fire on the island which covered about 5000 square metres.
Witness Mikee Tucker said Sunday's fire started at Kaitoke Creek and understood it had been caused by a camp cooker.