The National Party is promising the freshwater standards coming into force next week will be "gone by lunchtime" if elected.
The legislation passed this month puts controls on farming practices such as winter crop grazing and feedlots and sets stricter limits on nitrogen pollution.
The regulations were described by lobby group Federated Farmers as "unworkable".
Federated Farmers water spokesperson Chris Allen said: "As drafted many farmers will end up being unable to comply, an outcome we are sure is not the government's intent".
Today, minister for agriculture Damien O'Connor announced changes to the winter grazing regulations to make them more practical.
"It became apparent that some of the regulations within the freshwater standards - including ones around winter grazing - need to be adjusted, so we've done that.
"The regulations on pugging depths around fixed water troughs and gateways weren't practical so we have made some adjustments to make them more realistic."
Discrete areas around fixed water troughs and gateways had been exempted.
"We've also amended the definition for pugging to provide more clarity," he said.
Mr O'Connor said there were still some challenges ahead, but he was confident they would get it right.
"Where the regulations are impractical or unclear we will continue to make adjustments."
'Gone by lunchtime'
In a Facebook Live video last night, National leader Judith Collins and agriculture spokesperson David Bennett said their party would do away with the regulations, accusing the government of not liking farmers.
"So, David, can we tonight promise, because this makes me very angry that these people would do this, that we'll get rid of them," Collins said.
"They are gone by lunchtime," Mr Bennett replied.
Those comments are being described as reckless and dangerous by the Green Party's environment spokesperson Eugenie Sage.
"The new leadership of the opposition is trying to take their party back decades by saying rules to look after the health of rivers 'would be gone by lunchtime' if they were in power," she said.
Ms Sage said the Greens were committed to strengthening the standards to make sure nitrogen limits are based on the best science and that regional councils have enough resources to ensure healthy rivers.
"New Zealand's valuable food and fibre exports rely on our clean green reputation internationally, it's important that environmental safeguards are upheld to help maintain that.
"The opposition wants to throw out these safeguards, yet have no plan to clean up waterways and stop pollution in urban or rural streams and rivers," she said.