Farmers are being urged to check sheds and chemical stores for DDT or other banned pesticides as The Great DDT Muster does a final sweep of the country.
Funding for this free collection and disposal service for persistent organic pesticides (POPs) is coming to an end but the company responsible for the service, 3R Group Ltd, believes there is still more out there.
3R's ChemCollect manager Jason Richards said its government funding is coming to an end, to send these particular chemicals to France for safe disposal, and they know POPs are still out there.
"If farmers think they might have DDT or anything similar in their sheds, we'd really encourage them to book free collection and disposal with us before the end of October. It might be their last chance."
Mr Richards said people are not willfully holding on to the chemicals. They are either unaware of what they've got, unsure how to safely dispose of them, or unwilling to pay for commercial disposal.