The council has granted land use consents and compliance certificates to Five Rivers Ltd, Southdown Holdings Ltd and Williamson Holdings Ltd for the farms, which would run up to 17,850 cows.
All three fall within the rural scenic zone under the council's district plan but outside the outstanding landscape areas.
The consents and certificates were not publicly notified and were issued in September and last month.
Each of the three companies has received land use consents for intensive farming and earthworks, and two certificates of compliance for water take structures and crop production.
Planning manager David Campbell said resource consents were required to be publicly notified - allowing people to make submissions - if the effects were considered more than minor.
In the case of the dairy farm developments, the council considered the effects were noise, odour, dust, rural amenity and visual effects resulting from intensive farming.
"We deemed those effects would be no more than minor as the sites are very isolated and there is considerable separation [from] any established residential dwellings," he said.
There were no special circumstances which would lead the council to conclude the applications should be notified, nor were any affected parties identified.
The council's hearings panel was consulted in making the decision not to notify the applications.
The council consulted the Department of Conservation, which had no concerns.
It also liaised with Environment Canterbury (ECan).
The council had no authority under its district plan nor the Resource Management Act to deal with animal welfare issues, because any farming operation would have to comply with other legislation, such as the Animal Welfare Act.
The council also could not look into other issues such as the effect on tourism or New Zealand's image.
The dairy sheds could not be seen from State Highway 8 and a conditions on the consents required landscaping around each shed.
Issues associated with discharges, such as disposing of the effluent, fell under ECan's jurisdiction, Mr Campbell said.
The developments still require resource consents from ECan for water for irrigation, storage of effluent, disposal of almost 1.8 million litres of effluent a day, and to construct cubicle barns which will house the cows full time for eight months and 12 hours a day for four months.
The irrigation consents are at present being heard by an ECan panel, while public submissions have been called for on the other consents.
They close on December 18 for Five Rivers and Southdown, and January 18 for Williamson Holdings.
