The Animal Health Board (AHB) has issued a warning to Hawke's Bay hunters after a feral pig was found to have tuberculosis.
The disease was found during an annual tuberculosis survey of pigs in Mohaka Forest, 33km southwest of Wairoa.
"Pigs are considered a great indicator species as they tend to scavenge. If possums are infected, it gets passed onto pigs and they, in turn, can also infect cattle and deer, perpetuating the disease cycle," AHB southern North Island regional coordinator Terry Hynes said.
Pig surveys and testing of all cattle and deer herds would continue in Mangaorapa, Te Uri, Owhaoko, Te Pohue-Tarawera and Wairoa until there was no evidence of the disease, he said.
"TB lesions are most commonly found in pig heads. This is why we work closely with local pig hunters in designated areas and ask them to submit heads for surveying."
Mr Hynes said the infected pig was a timely reminder to all hunters about the dangers of introducing pigs into an area and setting up new infection sites.
"Pig hunters ... bring in new blood, pigs from other areas, and they can in turn affect the possums in that area, and that is the key to it," he said.
Tuberculosis was not unusual in the area and showed up "in the odd animal" each year, he said.
"We manage it, we still have the disease there so we've still got to continue with our routine control operations.
"The thing is, even though we're not finding infection in the cattle or deer herds ... we still have a problem in the wild animal population and we still have to keep targeting that."