Flames as high as four metres ripped through farmland in Cable Bay, threatening a nearby pine plantation, with sparks from a roadside grinder possibly to blame.
About 50 firefighters and two helicopters with monsoon buckets fought a fire covering eight hectares on Ian and Barbara Stuart's property on Cable Bay Rd from 3.30pm to 9.30pm yesterday.
The fire did not threaten houses, but Waimea Rural Fire principal fire officer Ian Reade said it was about 30 metres away from igniting heavier fuel - thick gorse, leading into a large pine forest.
"If it had got into that thick gorse, and then the trees, it would have been a very serious fire," he said.
"It looks like it could have been grinding sparks from somebody doing some grinding on the edge of the road, and it has caught into the dry vegetation."
A fire investigator was looking into the cause, and "the person responsible for starting the fire is liable for the cost".
Mr Reade said a fire of that size, which tied up two Nelson Marlborough Rescue helicopters, could cost about $60,000 to $80,000.
"We won't necessarily prosecute, it's just a matter of getting the bills paid," he said.
Mr Reade said residents called emergency services about 3.30pm, and the helicopters and Nelson Fire Service were first on the scene.
Waimea Rural Fire crews took over from the fire service, with volunteers from Hira, Appleby, Motueka, and Brightwater.
Civil Defence and the police were also on site, although evacuations were not needed, and Nelmac firefighters also pitched in.
"We had it contained pretty much by 9pm. It was quite steep country. The guys did a tremendous job."
Mr Reade said firefighters were on watch last night, in case of any flareups, and they would be dampening down hot spots today.
Mrs Stuart said she could smell charred ground from her Cable Bay home this morning.
"A spark from a grinder started the fire, and by the time they got their fire extinguisher, it wasn't enough to stop it. The southwest wind just fanned it, and it was away," she said.
"It was just an accident. Ian and I felt really sorry for them, because they didn't want to start a fire. They were really shocked and shaken that it had taken off so quickly. It's just so dry. If it was in town, it wouldn't have got away."
Mrs Stuart said she and her husband were grateful the fire crews were able to stop the fire from getting into the 120ha pine plantation they owned with other people.
The Stuarts have had a tough run in the last couple of years, with devastating flood damage on their property in 2011.
"It's stressful, but it's life. It [the fire] will mean a lot of work with re-fencing. It has definitely been a tricky patch. That's farming, you have to roll with the punches."
Cable Bay resident Simon Fletcher said he and his family left their home when they saw the smoke. "We got out of there. We were worried enough to leave for our own safety," he said.
Web designer Clint Fern saw the blaze from his house on Maori Pa Rd, about 4pm.
"It was big when I noticed it. There's a lot of kanuka and gorse around here, so if it [a fire] got going, it would be time to leave."
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