The body running the national scheme to eradicate bovine tuberculosis from cattle and deer herds expects to complete a funding review in August.
TB Free New Zealand spends about $80 million a year on the programme. More than half of that goes on possum control and surveillance.
William McCook, chief executive of TB Free's parent body OSPRI, said funders, who included the Government and farmers, had asked for the review of how the costs are divided.
"The TB programme's a significant activity and over five million TB tests of farms occur every year and then we've got a possum control and surveillance programme that runs over about ten million hectares."
Mr McCook said contributing to the TB scheme were farmers in the dairy, beef and deer sectors, the Crown and landowners in regions where there were possum control and surveillance programmes.
"So the funders have asked that we review and define the principles about how we actually allocate the costs between them and also look at some of the broader benefits of the TB scheme, particularly around biodiversity, with all the pest and possum control that we do."
Waikato Regional Council has agreed to continue its $650,000 contribution to the TB eradication programme for one more year, while the review continues.