Lives, incomes, asset values and mental health will all be at risk under the One Plan as directed by the Environment Court this year, with figures showing the $105m economic loss would be multiplied three or four times in the trickle down to the district.
"This community has found solutions, showed their patience and have led New Zealand on the environmental front.
"They won't give up and we won't give up," Mr Phillips said.
Thursday's public meeting was called by National Wairarapa MP Alastair Scott and attended by Speaker of the House and former Minister of Agriculture David Carter, along with representatives from Horizons.
"National is the only party on the side of farmers and in the face of Labour's stance on water tax, the emissions trading scheme and capital gains tax, we cannot afford to have a Labour/Green government with or without New Zealand First," Mr Scott said.
"Along with all that, Tararua farmers are faced with the added burden of the Horizons Regional Council One Plan.
"People think waterways were clean 20 or 30 years ago, that's just nonsense.
"The opposition is taking advantage of a lack of understanding and putting a water tax on irrigators, when the dirtiest waterways are in Auckland."
Dairy farmer Philip Hartridge said the One Plan problems were the "canary in the mineshaft" for New Zealand because of the gravity of the situation, especially in the priority catchment of the Tararua.
And with the Resource Management Act partly to blame for the situation farmers found themselves in, Mr Scott warned National needed a clear mandate at the polls on Saturday, otherwise farmers could still be sitting in limbo.
Horizons Regional Council has had to rethink how it implements its One Plan after a judgment handed down by the Environment Court after Fish and Game and the Environmental Defence Society (EDS) took a case to the court this year.
"I'm sure when the Environment Court judges handed down a resolution like they did, they didn't really care," Mr Phillips said.
"As it stands, all the mitigating strategies put in place by dairy farmers to protect and improve our environment will stop, so what we want to see is a plan change."
Although he acknowledged Horizons staff were now working well with Tararua farmers, Mr Phillips said they should never have let the current situation occur.
There are 265 dairy farmers in the Tararua, 133 have consents, with 132 farms still to go through the process.
"Even those who have consents will be challenged legally by Fish and Game and EDS and to meet the criteria will cost farmers between $30,000 and $50,000.
"Even if farmers meet the consent level, they're probably going to go broke anyway."
Mr Carter said when he was minister for agriculture he was immensely worried about the One Plan as it was developing.
"The effect of the plan is at its very worst in Tararua," he said.
"The Resource Management Act simply isn't working and National had some very definite plans to reform the act, but we simply didn't have the numbers in Parliament so it was a minor tinkering which has had no significant effect."
Makotuku farmer Will Findlay, also a member of TCEIS, said what radicals were saying about the quality of our water was "rubbish".
"We can drink the water from our rivers," he said. "These people need some pushback. It's treason, they're lying."
Mr Carter said he wasn't disagreeing.
"Too many people are having a say in the process who don't have skin in the game," he said.
"It's about the environmental impact of your community, but also the economic and social impact.
"Speaking as a farmer, I personally think it goes back to the dirty dairying debate. It's been festering in urban New Zealand, with bullshit and lies.
"None of us in agriculture want to ruin our environment."
And although Horizons chairman Bruce Gordon said his council was negotiating with Fish and Game and EDS, Dannevirke lawyer David Roberts had a warning.
"There's a reluctance to review the plan," he said.
"Fish and Game and EDS have won in the Environment Court, so why would they negotiate with the regional council? I think you can expect them to bring it back to the Environment Court."
However, Mr Gordon said the groups were "keen to talk to us".
And Nic Peet, Horizons group manager for strategy and regulation, said while the idea of the regional council coming out and prosecuting farmers operating without a consent wasn't in the public interest, the council had taken legal advice.
"Fish and Game and EDS aren't interested in prosecuting individual farmers, their issue is with us," he said.