A group of wild pigs have been illegally released by hunters in bush at Raglan, prompting fears of an outbreak of tuberculosis.
Wild pigs can carry TB, according to the Animal Health Board.
They have the potential to infect areas in which the existing wildlife population is free of the disease, particularly if hunters leave the head and offal in the bush.
Possums and ferrets scavenging on this material can become infected and spread the disease to cattle and deer.
The Department of Conservation says it will do "whatever is necessary" to stop the pigs becoming established and damaging native plants.
Neighbouring farmer Phillip Swann, who operates a 200-hectare beef and sheep property, said he had recently seen an influx of wild pigs around his farm, an area previously cleared of TB in wild animals.
"As a beef farmer, I have a lot to lose if TB rears its head in this area. People need to consider the possible consequences of transporting and releasing wild pigs that could well be carrying the disease.
"It's about educating people who release these pigs that enough is enough.
"We're talking about farmers' livelihoods here which could be threatened if TB was introduced," he said.
The board's northern North Island programme manager, Brent Webster, said hunters should also be aware of the risks when handling infected wild pigs.
Humans can get TB from infected animals or their carcasses.
"You should always practise good hygiene when hunting wild pigs, including disinfecting all knives and other gear after use, cover any cuts on your hands and arms and wash after cutting up animals."
DOC Waikato manager Matt Cook said the deliberate release of pigs into conservation parks and reserves was an offence under both the Reserves Act and the Wild Animal Control Act.
"The department has spent a great deal of time and effort over many years clearing wild goats, feral cattle and other pests from Mt Karioi - part of the Pirongia Forest Park - due to the extensive damage they inflict on our native species," he said.
- © Fairfax NZ News