A ferret survey is being undertaken in the Mt Cargill area, near Dunedin, after last year's bovine Tb outbreak.
Four herds of cattle and deer were identified as infected with Tb.
In a recent update, TBfree southern South Island programme manager Brent Rohloff said work had been progressing well.
OSPRI was using a combination of herd Tb testing, controls on animal movement for infected herds, and survey and control of wild animals to eradicate Tb from the area.
As Tb had been found in six possums and one ferret, further surveillance work was needed to determine the extent of the infection in local wildlife.