The Ministry of Primary Industries (MPI) says testing of New Zealand milk products for DCD residues will continue despite no further traces being found in any milk collected from farms since mid November.
The ministry and fertiliser companies revealed last month that minute amounts of the chemical compound had been found in some dairy products as a result of some farmers using nitrification inhibitors in fertiliser to reduce nitrogen leaching.
Sales of the inhibitors have been suspended and MPI and dairy companies have tested almost 2000 samples, targeting milk collected from mostly South Island dairy farmers who used DCD on their pastures.
MPI director general Wayne McNee said while there may be still products with DCD in the supply chain, nothing has been found in milk processed after farmers last applied it.
He said DCD was applied in spring and no product has been applied since then. No traces have been found of the product in any milk collected after 13 November.
Mr NcNee said there will be an ongoing testing programme and MPI will work with markets to look at setting an international minimal standard for DCD.
He said no DCD will be applied to pasture from now on, but at some point it may be applied again if a minimum standard is put in place. MPI said that process is likely to take several years.
Mr McNee said overseas markets accept New Zealand dairy products are safe but regulators in those markets have complained about the lack of notice they were given.