United Beverages, the Guinness-owned company whose Dundalk plant is involved in a dispute with SIPTU and the ATGWU over pay, yesterday said that if the dispute was prolonged "the future viability of the operation may be called into question".
The strikers, who comprise about half of the 54 workers in Dundalk, are in their fourth week of picketing.
The dispute centres on a claim that the Dundalk employees are paid about £120 a week less than their counterparts in a Dublin plant, also owned by United Beverages.
The Dundalk plant bottles and distributes the Finches brand of soft drinks to the licensing trade.
In a statement yesterday, the company said the industrial action had "severely impacted on the business in Dundalk through loss of supplies of Finches products and disruption of distribution to customers in the north-east".