Matakanui Station owner Andrew Paterson estimates it will cost him about $1.6 million to comply with the new freshwater rules for fencing off waterways on his Central Otago hill country property.
He will also have to take about 47ha out of use to follow the 5m buffer rule.
The National Policy Statement for Freshwater Management 2020 sets out new objectives and policies for farming including waterways, nutrient losses and winter grazing and the rules come into effect today.
He agrees with Federated Farmers Southland president Geoffrey Young that some of the rules are unworkable and supports Young's recent call for a boycott of the new rules.
"I believe the Government has to relook at this. They say Federated Farmers was consulted, and we made submissions, but I think the rules show we were not listened to.
"Much of the plan is not common sense."
He and wife Tracy have 5100ha of freehold land and 3600ha leasehold land.
The property near Omakau ranges from 280m to 1600m in height and the couple run about 20,000 sheep and 1100 cattle.
He is concerned about 500ha of steep to mountainous area, which he uses year round for stock grazing.
In the new rules, waterways in "low slope areas of less than 10 degrees" have to be fenced off.
However, the Government had used Land Information New Zealand's Primary Parcels data, which Paterson said incorrectly showed that particular area as having slopes of less than 10 degrees meaning he would be required to fence it.
"That is ridiculous."
Paterson said that would be about 42km of fencing, therefore at $20,000 per kilometre, plus replacement stock water systems, it would cost him about $1.6 million.
"It was very poorly done, poorly thought out, poorly planned and poorly mapped."
The mapping problems have been acknowledged by Agriculture Minister Damien O'Connor and Environment Minister David Parker and are being investigated.
The updated rules state that pugging (penetration of soil of more than 5cm) should not be more than 20cm and should cover no more than 50 per cent of the paddock.
"It is impossible to avoid pugging in the winter.
"My ute can pug more than that on the flat," Paterson said.
In addition, the limited time frame of November 1 to have crops in the ground for planting crops did not make sense to him, especially for Otago and Southland, given how wet the regions could be about that time.
Most farmers in Central Otago preferred to plant their next winter's crops close to Christmas to take advantage of any rains at that time.
"If we plant too early it gets too dry and the plants struggle."
He acknowledged many of the new rules would benefit the environment.
"However, the stupid thing about the consents themselves is they don't make the environment better.
"We are paying at least $1500 per consent and if the councils do not have enough staff to process them, that means many farmers will automatically be in breach of those consents as they cannot get them [when they need them].
"The rules brought in by Government have not been thought through."