Crossborder milk processor LacPatrick has followed the suit of its soon to be the business partner Lakeland Dairies in holding its price in one jurisdiction and dropping in the other.
A spokesman put the differential down to currency differences, saying that sterling had fallen from 87c to 85c.
It means for the month of February, producers in the Republic of Ireland will see their standard litre price held at 31.75c plus a 2c/L early calving bonus.
However, in Northern Ireland producers will see it slide 0.75p, from 26.5p/L to 25.7p/L.
LacPatrick has around 1,300 suppliers - a figure which includes around 700 farmers in Northern Ireland and 600 south of the border.
However, in a silver lining, all LacPatrick suppliers, regardless of their location, will see their transport charges removed for the month.
Cartage is currently paid by all members of the co-op and averages at around 0.25p/L or 25c/L.
While the gesture will not mitigate the reduction in price for northern suppliers, it will go some way in easing the drop on this month's cheque.
The offer of free transport is expected to be carried forward into the new Lakeland Co-op assuming suppliers opt for every-other-day collection.
LacPatrick Dairies chairman Andrew McConkey said: “The board of LacPatrick has agreed to remove the cartage charge for all our suppliers in Northern Ireland and the Republic of Ireland. We are pleased to be in a position to do so."
The merger between Lakeland Dairies and LacPatrick Dairies is scheduled for completion by March 29 – the same date as Brexit is currently scheduled for.