Hunters should not take animal carcasses for human consumption from areas where brodifacoum poison is used, the National Pest Control Agencies say.
Brodifacoum poison is an anti-coagulant chemical.
If ingested by animals, including humans, it inhibits blood clotting, causing death from internal bleeding.
Brodifacoum is a predominant toxin used in Environment Southland possum control areas (PCAs) by both farmers and contractors in Southland.
The National Pest Control Agencies factsheet on the poison states commercial hunters cannot hunt wild animals for consumption in areas where the poisons have been laid, including the buffer zones, until the specified caution period of three years has elapsed.
The buffer zone is within 5km of the poisoning area for pigs and within 2km of the poisoning area for large species such as deer.
The same buffer zones and caution periods are also recommended for recreational hunters.
Environment Southland senior biosecurity officer Dave Burgess said it was a legal requirement that wild animals could not be taken for ''commercial markets''.
When setting up a new PCA, Environment Southland now included this in the discussions with landowners.
When it came to farm animals, they should not have access to brodifacoum bait or bait stations, Mr Burgess said.
''They normally get this information at least twice in the first two years.''
Brodifacoum was a predominant toxin used for Environment Southland PCAs by farmers and their contractors that had bait stations, he said.
''It is also a common bait sold over the counter and online to the general public for both rodent and possum control.''
Along with the poison, a warning sign was required to be erected at normal points of public entry to any area/property where it was being used, he said.
''These signs must stay up for at least nine months after baiting has ceased. In the case of properties which are part of our PCA programme, we supply farmers with appropriate warning signs.''
The Department of Conservation took a precautionary approach to using brodifacoum.
DOC Murihiku operations manager Tony Preston said current policy allowed the poison to be used on off-shore islands for operations such as one-off rodent eradication projects.
''However, on mainland public conservation land, brodifacoum is not a common pesticide used on public conservation land by the department or community groups, due to environment and bio-accumulative concerns,'' he said.
When it was used, signs notifying the public were required to be in place for up to 36 months after the pesticide application, he said.
Trapping and cyanide were other common ways of controlling pests and in PCAs in Southland the decision was up to the landowner, Mr Burgess said.
''For those with bait stations, brodifacoum is a very efficient and cost-effective possum control tool which doesn't require a licence, but must be used according to best practice and label. It is/has provided extensive biodiversity gains throughout the country for many years. There is little/no poison shyness due to its slow action of working.''
Brodifacoum could be bought over the counter without a licence, he said.
It must be used in a bait station and label instructions must be followed.
There are industry guidelines for bait station use, which, along with the label, can be found on the National Pest Control Agencies' and/or Animal Control Products' websites.