A row has erupted over Glanbia’s decision to raise the price of milk when the euro is introduced in January.
The food group plans to change its half-pint cartons into smaller 500ml cartons without changing the price.
SIPTU has described the move as a rip off and said it will increase the cost of living in Ireland.
Consumer Affairs Minister Tom Kitt also criticised the move.
"It is clear to me that this announcement from Glanbia has nothing whatsoever to do with the euro and I think it is misleading and nothing more than a smokescreen to suggest otherwise," he said.