A Marlborough District Council report suggests enforcement action might be needed against dairy farmers who fail to meet environmental standards.
A survey of the district's 54 dairy farms shows that while overall compliance is improving, it also highlighted a number of farms which don't meet standards and fail to heed warnings to improve their systems.
The report shows very few farms have dairy shed effluent systems that meet current industry best practice standards, and many are reluctant to improve collection, containment and application systems.
While there has been a decline in dairy herds crossing streams, the council's goal was to have all stopped by December 2013.
Marlborough Federated Farmers dairy division chair Evan White said farmers were waiting for sign-off on the council's updated environmental plan before investing large sums in systems that would meet new compliance standards.
Mr White said some farmers meet the standards under the council's current environmental plan, but not under the proposed plan.
"You'll find there are a number of farmers at the moment that are looking at upgrading, they just want to know what they have to do to be compliant.
"They do not want to spend $100,000 or more on a system if council's then going to turn around and say 'no, that's not good enough'."
The council said there had been a decline in dairy herds crossing streams, but its goal was to have all stopped by December 2013.