The fires were discovered in Westland National Park near the Okarito Kiwi Sanctuary, about 25km north of Franz Josef. The sanctuary is home to the rarest kiwi species, the rowi, of which only 350 remain.
Four fires were spotted from a helicopter about 3am yesterday, while another suspicious blaze was discovered overnight by the side of State Highway 6. A helicopter with a monsoon bucket, firefighters and Department of Conservation (DOC) staff tackled the first blazes, the largest of which spread over about 500sqm of the Pakihi wetland.
Richard Saunders, who operates Okarito Nature Tours, said it was likely that hunters had targeted the wetland because the area was very dry above ground but wet and swampy underneath, allowing grass to regenerate quickly.
"Deer come in to graze on the new growth and they're easy to shoot from the convenience of your ute or your SUV," he told NZPA.
"It's lazy, lazy hunting. There's plenty of deer in the forest, and no one has any problem with people who are hunting the right way, but this is just incredibly lazy and at a massive cost to the taxpayer." The fires had done a lot of damage to the wetland, he said.
"They are very fragile ecosystems. There's lots of bird life in it, like endangered fernbirds, and they're slow fliers." The community was "very angry" about the fires, Mr Saunders said.
"We're pretty proud of where we live, it's a beautiful part of the world, and then visitors to the area are now driving through the charred remains of a wetland to get here." With only a few hundred people in the area, it was likely someone knew who had lit the fires, he said.
"The more pressure brought about, the more likely someone will talk," he said.
"If there was a smoking gun like a charred kiwi, they'd be coming down like a ton of bricks." Ian Cooper, the only person authorised to take people on tours into the sanctuary, said fires had been lit "every couple of years" for at least 20 years.
"It seems to be a residual thing -- dad does it, so it's okay. But it's not okay. Even though they've been doing it a long time, it doesn't mean it's right," he said.
Rowi often ventured out of the sanctuary area, and the Pakihi wetland was known to be part of two kiwi territories.
"Potentially we could've had...birds (in the wetland area) killed just through lazy hunting," he said.
"The worst case scenario, it could have wiped out the whole lot. The bush is as dry as buggery out there at the moment."
Mr Cooper was disappointed that DOC's work to educate the local community about the rowi had not got through to some people.
DOC staff had stepped up their vigilance in the area, and would this week assess whether the rowi population or environment had been affected.
