Jacinda Ardern has bagged National's "backward-looking" agriculture policy and insists Labour "absolutely" understands the needs of the farming community.
The National Party's agriculture policy includes tweaks to the Government's plan to tax agriculture emissions, changing the Zero Carbon Act, repealing new water regulations and altering how forestry emissions are taxed.
Ardern said it was "hugely disappointing" that National wanted to repeal much of the work her Government had done around regulations to clean up waterways and coming to an agreement with farmers to tax their emissions.
National supported the Zero Carbon Act last year to become law, but it's promising to make changes if elected, including a review of the methane reduction target of 24-47 percent by 2050, which some farmers say is unrealistic.
Agriculture contributes around 48 percent of New Zealand's emissions. Methane is produced by ruminant animals, or animals that have four parts to their stomach, including farm animals such as cows, sheep and goats.
"From what I've seen, the policy put out by the National Party would take New Zealand back decades... It is hugely disappointing to see that change in position from them," Ardern told reporters in Christchurch.
"On issues like climate change we did have consensus. To now see the National Party change its position is deeply disappointing. It takes New Zealand backwards and it also hurts our brand, which we trade on and which we are growing our exports over."
Stats NZ data shows that New Zealand's exports have grown over the past year with milk powder, butter and cheese exports up 11.1 percent, meat exports up 9.9 percent, wine exports up 8.5 percent, fruit exports up 8.4 percent and vegetables exports up 6.3 percent.
National wants to put a stop to what it calls the Government's "unscientific and arbitrary" synthetic nitrogen fertiliser cap. Dairy farmers are required to report annually to councils the quantity of nitrogen applied per hectare as synthetic fertiliser.
The rule was announced in May as part of the Government's $700 million commitment to clean up waterways, which also included controls on higher-risk farm practices such as winter grazing and forcing farmers to develop farm environment plans.
"It's fair to say that when we came into office our waterways were in a terrible state," Ardern said. "People couldn't swim without concern over getting sick. We made a pledge to do something about that and we have, and we've done it working alongside our farming community."
She said it's "very disappointing" to see National plan to "unravel" the Government's work.
Agriculture was a hot topic in Ardern's first TV debate against National leader Judith Collins earlier this week, with Ardern coming under fire on social media for a quote about farming she says was taken out of context.
Ardern said of the agriculture sector, "that feels to me like the view of the world that has passed", after Collins had talked about farmers feeling "bagged" by the Government over new regulations aimed at combating climate change.
Collins says farmers are sick of regulations and believes Labour doesn't understand them.
"Farmers have enough on their plate with weather, interest rates, and international markets, they shouldn't have to contend with a Government who doesn't understand their sector and restricts their growth," she said on Thursday.
"When we form the next Government, our pledge is to ensure that our agricultural policy focuses on allowing farmers the opportunity to farm their way to better outcomes, rather than being regulated into oblivion."
But Ardern says Labour does understand farmers.
"Absolutely," she said. "We've been working alongside our primary sector to develop these solutions. We have the same goal - everyone wants to improve the quality of our waterways and we're working together now to get that implementation right."
National also plans to tweak the Government's arrangement with farmers to start taxing agriculture emissions by 2025.
Farmers have been given time to develop ways to measure and price emissions at the farm-level, to be separate from the ETS. But if they can't figure something out by the time a review comes around in 2022, agriculture could be included in the ETS.
That wouldn't happen under National, and Ardern says that's disappointing.
"We have consensus now with our farming leaders, that took a lot of work, and it would be a shame to see that unravelled by backward-looking National Party policy."
National argues it doesn't support the clause because "it creates needless uncertainty and signals Labour aren't 100 percent committed to the farmer-led programme".