The issue of winter grazing is back in the spotlight after an animal rights group released photos of cows in mud on Thursday.
SAFE accused the Ministry for Primary Industries (MPI) of "an outrageous failure" to enforce rules aimed at protecting stock.
SAFE campaign manager Marianne Macdonald said the photos showing cows in mud-filled paddocks were taken by a resident in Fiordland in early June.
After seeing the cows, the person laid a complaint to MPI but two weeks later nothing had been done, Macdonald said.
"This is an outrageous failure on MPI's part and we demand that they do more to protect these animals," she said.
Last year winter grazing - where animals are strip-fed a crop - received nationwide attention after a campaign sought to highlight the issue.
Activists say the practice is an environmental and animal welfare issue.
"Cows kept in muddy paddocks are unable to rest comfortably and are at risk of painful health problems such as mastitis and lameness," Macdonald said.
Following last year's campaign, a task force was set up by Agriculture Minister Damien O'Connor, and then in March this year, an action group was launched to implement recommendations to improve animal welfare grazing systems.
But Macdonald said a separate Crown entity should be established with the sole function of ensuring adherence to New Zealand's animal welfare laws.
She said the conditions in the photos were "likely a breach" of rules established for inspectors to enforce.
MPI director of compliance Gary Orr told Newshub the ministry had investigated the complaint but was "satisfied there were no animal welfare concerns".
Inspectors visited the property on June 10, two days after the complaint was laid, Orr said.
"Upon arrival, the inspectors' observed 180 dry (non-lactating) dairy cows on the paddock associated with the complaint. Many were comfortably lying down and resting. It was noted that there were plenty of dry areas available.
"The cattle were all in good condition and had no signs of health issues. Good quantities of supplementary feed, such as hay and silage, were available and all the cattle had easy access to clean drinking water."
Orr said heavy rain the previous weekend had contributed to the mud and recommended the farm's drinking trough be moved regularly to avoid a repeat of the conditions.
Bernadette Hunt, Federated Farmers' vice-president in Southland, says MPI did a thorough investigation and it was "really disappointing" SAFE was "continuing to hassle" the farmer in question.
"When it rains the ground gets wet that's just a fact of life, but all of the right things are in place to ensure that the cows are looked after," Hunt told Newshub.
She said SAFE had "unrealistic expectations" about conditions on farms.
"Farmers can't stop the ground from getting wet when it rains. The cows are well fed and well looked after, they've got plenty of space, places to lie down that aren't muddy or wet and sloppy."