Food and agri-business company Donegal Creameries has warned that its profits "will be substantially below market expectations" for 2004.
The company said that the tough climate in the dairy sector had continued into the second half of the year.
Milk-procurement costs were high relative to the market price, particularly in Northern Ireland.
The company's potato operations, which generate most of its profits in the last quarter of the year, also performed below expectations.
This was blamed on high oil prices, which drove up freight costs, combined with a bumper harvest in mainland Europe, which depressed selling prices.
Despite having agreed a number of substantial asset sales, these sales are subject to planning permission, which is taking longer to obtain than previously expected.
As a result, the directors of the company will not include the income from those sales in the 2004 accounts.