Northland MP Winston Peters has called on the Prime Minister to attach a choke chain to Primary Industries Minister Nathan Guy, and to use it, after news that Mr Guy has his officials developing an Import Health Standard for animal manure.
"Few things this National government does surprises me any more, but allowing in European animal manure to grow mushrooms really does beat all," Mr Peters said.
"We're not short of what comes out the back of farm animals, and if this wasn't so short-sighted and stupid it would almost be comedic.
Our farmers are under siege from all and sundry on the question of animal excreta. They are trying to deal with it, so why on earth import more of it from offshore?"
Mr Guy had said the risk of exposing farmers and growers to an outbreak of something economically crippling, like foot and mouth disease, was low, but Mr Peters saw no sense in raising the risk given the country's "already leaky biosecurity system".