Farmers on the east coast of the North Island are preparing for a scrap over scrub.
They are worried about a proposed national policy statement from the Ministry of the Environment on managing native biodiversity.
Federated Farmers says it would force councils to impose rules restricting farmers' ability to clear regenerating scrub, particularly manuka and kanuka.
''The scope of this will require councils to protect all indigenous vegetation, in effect, all farmland in New Zealand,'' says Gisborne-Wairoa president Hamish Cave.
Mr Cave says Federated Farmers will oppose the policy proposal in submissions. He says some landowners could lose most of their land to regrowth, which would have a devastating impact on small rural towns like Wairoa.
Farmers in Taranaki have raised the same concerns.
Conservation Minister Kate Wilkinson says the concerns will be taken seriously.