Fonterra dairy co-operative says it was unable to collect milk from just over 2000 farms on Tuesday due to snow and ice conditions.
Fonterra has 10,500 farmers supplying it with milk. As a result of the non-collections, farmers had to dispose of an estimated 9.5 million litres of milk.
Some were able to feed the milk to calves, but others had to pump the milk into effluent holding ponds.
Fonterra says it's working with regional councils on the milk disposal issue.
Road closures meant milk tankers were unable to reach about 1700 dairy farms in snow-bound areas of the South Island on Monday.
Taranaki Regional Council says it's still early in the milking season and most farmers have coped with not having a collection.