Close to 300,000 stock units will be lost this year from the Wairoa, Pongaroa and Wairarapa areas alone thanks to new farm forestry, according to a new national organisation 50shadesofgreen.
The problem, spokesman Mike Butterick said, was that it was not just steep hill country that was being planted. Productive farmland was disappearing under trees too.
The organisation was also concerned that the government's tree planting programme would create the "zombie towns" that economists were predicting.
"We are not opposed to forestry on land appropriate for trees. We are strongly against highly productive farmland being lost to food production forever," Mr Butterick said.
"I don't believe the government has the faintest clue what its programmes are doing to the provinces.
"Our view is that they're a wrecking ball hitting food production and rural employment.
"We urge the government to immediately rethink its policies and talk to food producers."