Regional councils in Waikato, Bay of Plenty and Northland are advising farmers who have to dump milk as a result of the closure of the Maui gas pipeline to keep it out of waterways.
The councils say most farmers lack the capacity to store milk for more than a day or two, and will have to make emergency disposals if processing plants remain out of action beyond that.
Waikato Regional Council says there are a number of ways to do that, such as irrigating onto paddocks or storing in effluent ponds.
It says farmers should follow the advice of their dairy companies and do all they can to avoid milk getting into waterways either through overland flow or direct discharge.