Fonterra Cooperative Group, the world's biggest dairy exporter, says yesterday's earthquake in north Canterbury did not cause any major damage to its manufacturing sites, with all staff safe.
However, it expects disruption to milk collection and farms that cannot be reached may have to dispose of their milk.
Miles Hurrell, Fonterra's Farm Source chief operating officer, said the Auckland-based cooperative will contact farmers directly if that was required.
"We're doing our best to reach everyone who is due for collection immediately. With power out and phone lines down in some areas, that includes putting Farm Source teams on the road to go door to door to try to update those farmers with the latest information," he said.
About 30 farms in the Kaikoura region may not have milk collected due to the state of the roads, while others may have late collections as routes are altered, he said.
Fonterra previously operated a factory in the town of Kaikoura, close to where the earthquake struck but shut the site earlier this year.
NZX-listed dairy group Synlait Milk has also told the market that it is operating as usual.
In a statement, it said some of its suppliers are located in the affected areas, and that it is working with them to manage any disruptions.
It did not expect the impact of this to be "significant".Units in the Fonterra Shareholders Fund rose 0.2 percent or 1 cent to $5.90. They've risen 17 per cent since a year ago. Shares of Synlait were unchanged at $3.08. They've risen 28 per cent from a year ago.