Britvic Ireland's brands include Ballygowan, 7UP, Club, Mi Wadi and Robinsons.
In a trading update, it said Irish revenue dropped 16.3% in euro terms compared with the same period last year. Its sales volumes for the full year were down 10.7% from a year earlier.
The company said the soft drinks market in Ireland showed no sign of a return to growth in the short-term.
Meanwhile, Premier Foods, which owns brands such as Batchelors, Mr Kipling and Bisto, has said its Irish sales in the third quarter of this year were 14% down compared with a year earlier.
In a trading update, it said the Irish grocery market had been difficult this year. The Irish fall contrasted with a 4% rise in sales in the UK.
