Environment Minister Nick Smith is urging Federated Farmers to jettison its so-called People's Accord and sign the Leaders Accord aimed at cleaning up the Manawatu River.
Federated Farmers says its accord better represents the facts about the river, which it concedes is degraded.
Its refusal to sign the official accord signed three weeks ago by 27 industry, council, environmental and iwi groups has led to its exclusion from the Leaders Forum driving the clean-up.
In a statement, Mr Smith says he has spoken with Federated Farmers' national leaders, urging them to reconsider their position.
He says united action is needed to clean up the river, which is why the Government has been such a strong supporter of the Leaders Accord.
United Future leader Peter Dunne says cost is the real reason Federated Farmers won't sign the Leaders' Accord.
He says the alternative accord is a joke and Federated Farmers should drop the charade and sign the Leaders' Accord.