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.