South Wairarapa's Aorangi Ranges will get a dose of 1080 poison this winter.
TBfree New Zealand is planning an aerial drop targeting possums within the ranges and surrounding farmland.
The organisation manages the national bovine tuberculosis (TB) control programme, which aims to get eradicate the disease by getting rid of possums, the main carriers and transmitters of it to livestock.
The Aorangi Forest Park is popular with deer hunters and trampers.
After consulting the community, the organisation will seek permission from affected landowners, the Medical Officer of Health, Department of Conservation and Greater Wellington Regional Council.
1080's is the only toxin currently registered for use on mainland New Zealand as suitable for aerial targeting of possums. Its use here has been controversial, with opponents saying it is cruel and also kills native birds and wildlife.
The NZ Environmental Risk Management Authority reviewed its use in 2007 and concluded the benefits of using 1080 clearly outweighed the risks, and approved its continued use in aerial and ground applications.
Dogs are also vulnerable and owners are warned to keep them well away from treated areas.