Tirlán, formerly Glanbia Ireland, is investigating after monthly milk statements were sent to the wrong dairy farmer suppliers.
Suppliers received the letters on Tuesday morning, however upon opening the letters, some realised that the incorrect milk statement in relation to their supply was included.
Instead, the statement of another supplier was included.
Supplier data included the milk price received, supplier number, herd number, volumes supplied and other details.
It is not clear how many suppliers are affected at this stage.
A spokesperson for Tirlán told the Irish Farmers Journal that the company "is aware of some issues involving this month’s milk statement mailing and we are investigating as a matter of urgency."
More to follow.