Some of the best Manuka honey in the country is failing the government's proposed new testing standards designed to protect the market from fake products.
That's according to an independent adviser to the Manuka honey industry who said up to 20 percent of the purest honey - worth about $10 to 20 million - is failing.
In April, the government put out its proposed scientific definition of what is Manuka honey and therefore what can legally be exported using that label.
MPI is still receiving submissions on the proposal but in the meantime producers have been testing their honey to see if they pass.
Independent adviser John Hill said he has had clients whose honey has failed under the proposed standards despite being some of the best in the country.
MPI's deputy director of general regulation and assurance Bryan Wilson said there was nothing wrong with the testing.
"Our test is designed to separate Manuka honey from other sorts of honey. We are pretty confident with the way we've got that set up," he said.