Fonterra is using alternative routes and extra trucks to collect milk from farms in the eastern Bay of Plenty which had been cut off due to flooding.
The Bay of Plenty has been inundated with up to 300 millimetres of rain since Thursday, leaving some farms cut off for milk collection.
Fonterra says it was unable to collect milk from about 90 farms on Sunday and those without adequate storage may have had to dump their milk.
But Fonterra's Edgecumbe operations manager Paul Rennie says they have now managed to get access to all their suppliers after roads reopened or detours were found.
He says Fonterra is having to use some back roads to gain access so the milk collection is taking a bit longer, and it's using two extra trucks to ensure coverage.
Mr Rennie says farming areas worst hit by flooding included Whakatane, Opotiki and Waimana.
The president of Federated Farmers for Bay of Plenty says about 20 farms in the region are under water on Monday.
John Scrimgeour says some farmers are worried about what land damage they will find once the water has receded.
"It's certainly not the start to the new year that they were hoping for. They are used to dealing with floods on a regular basis, and while they're disappointed by it, they will just get on and clean up and carry on."
Mr Scrimgeour, a dairy farmer, says he is not aware of any stock losses as farmers had plenty of time to move stock to higher ground.