Fonterra says its emergency response teams have contacted over 500 farms in flood-affected areas of lower North Island.
The co-op says around 30 farmers have requested immediate help, and the teams are on the ground working with them.
"Our staff are pumping out sheds, clearing slips, and working to get farms back in working order as quickly as possible," it says.
"We're able to collect milk as usual from all but three farms, and we're working to find other ways to get to those three as soon as possible."
Fonterra activated its emergency response team after severe flooding in Manawatu and Taranaki.
Any Fonterra farmer requiring urgent assistance can call 0800 65 65 68.