The sector-led group was set up in 2019 to work with the government to develop a world-first pricing scheme.
The Opposition has now declared the plan "dead" - a move Climate Change Minister James Shaw says may put the country's climate targets in jeopardy.
"I think it's dead, I think Damien O'Connor and the Labour government have killed it and I think it's all over," National MP Todd McClay said on Tuesday.
National contends the government has gone quiet on good-faith negotiations with the sector; an allegation Federated Farmers acting national president Wayne Langford backs up.
"What we need is government to really come back into the room and continue the discussions that we've been having for quite some time."
Climate Change Minister James Shaw told RNZ discussions have not stopped and National was "speculating into the void" for political gain.
"National are fighting with ACT over votes in the regions and in farming and rural communities and the ACT Party of course don't, as far as we know, even think climate change is real."
Shaw said Federated Farmers might be in the 'He Waka Eke Noa room' but recent events gave an indication of how little they were ever in the tent.
The minister was alluding to Federated Farmers former president Andrew Hoggard quitting his job early in May to announce he was standing for the ACT Party this election.
ACT opposes He Waka Eke Noa and the Zero Carbon Act - the country's legislative framework to curb emissions.
Shaw questioned the political motivations behind National backing down on climate commitments.
"ACT is pushing National very hard and trying to drag them away from the consensus position and unfortunately it looks like the National Party is succumbing to that."
The National Party said it has its own climate change policy it will share in the next few weeks but would not confirm this includes pricing emissions.
It has already committed to the 2050 net zero target and New Zealand's emissions budgets, which include agricultural emissions methane and nitris oxide.
Shaw said targets simply would not be met if the status quo continues.
