Greenpeace wants the New Zealand Government to immediately ban all farms being converted to dairy there but farmers say they have largely stopped anyway.
The environmental group said while it welcomed Monday's announcement of the NZ Government's plan for cleaner rivers, the changes would happen slower than anticipated.
A National Policy Statement on Freshwater Management and new environmental standards had been originally slated for arrival by the end of this year but they have been delayed until 2020.
"We need interim measures such as an immediate ban on dairy conversions and intensification of farms," Greenpeace freshwater campaigner Gen Toop said.
"There are already too many cows for our waterways to cope with.
"Yet there are new dairy farms being built and existing farms are still adding more cows.
Toop singled out the "precious and fragile" catchments of the Mackenzie Basin where 12 people were recently arrested for protesting over the building of a new farm where it was planned to put 15,000 cows on land just south of Lake Pūkaki.
Fonterra and Landcorp have opposed the development, and Federated Farmers has said it is "not ideal".
Feds environment spokesman Chris Allen said there were better measures to ensure clean water than a straight out ban on new dairy farms or intensification, and other developments such as housing sub-divisions also impacted on water quality.
"There are few conversions happening at the moment anyway. And if you ban dairy, can you then convert to another form of land use which is worse?" Mr Allen said.
"All we ask is that the Government uses an even hand. For example, the commitment to getting tougher on nutrient discharges to waterways needs to be applied fairly to both councils, corporates and farmers.
"Kiwis don't tolerate inequity. Implementing any changes to water policy will require the government to take the entire community along with it."
A report last year showed that in regions overseen by the Horizons Regional Council (Manawatu-Wanganui), Environment Canterbury and Environment Southland, conversions had almost totally dried up.
These are the regions that saw the most rapid increase in the numbers of dairy cattle, as farmers moved out of traditional sheep and beef farming in order to chase after "white gold".
Mr Allen described the time frame as challenging, but said farmers were continually introducing environmental improvements.
Ms Toop said the Government had promised "targeted action and investment in at-risk catchments, from now", but it was unspecific about what that action will look like.
The Greenpeace petition calling for a ban on new dairy farms and an end to further intensification of livestock farming has over 47,000 signatures.
Dairy NZ chief executive Tim Mackle said the industry-good body welcomed the report and was working with farmers to find out what changes they could make, especially over winter when soil was most at risk of damage.
It was monitoring planting at specific times of the year in Southland's Aparima River to improve soil condition and lower water contaminants.
Increasing numbers of farmers were using standoff pads or removing stock from paddocks when the soil was most vulnerable to compaction. Many were restoring wetlands and carrying out extensive planting to manage sediment loss and erosion-prone land.
"As a sector, we've recognised for many years that change is happening. We've acknowledged the impact dairy farming has had on the land and it will take time to fix some of the historical issues," Mr Mackle said.
The NZ Government has set up three working groups: Kahui Wai Māori to include a Māori voice, a Freshwater Leaders Group chaired by Synlait Milk founder John Penno, and a science group that includes crusading scientist Mike Joy.