There has been an outbreak of Legionnaires' disease at a Fonterra plant in the Manawatu.
The company has confirmed it found the bacteria Legionella in its Pahaitua site's cooling water.
A staff member and two contractors contracted the disease and were taken to hospital.
One of them has since been discharged.
The company says there is no risk to food safety or any products made at the site.
It says the contaminated water is used as a coolant only and the company has used chlorine to wipe out the bacteria.