Dunnes Stores has reopened its outlet in the Gorey Shopping Centre, four days after staff were told the store would remain shut until further notice.
A spokesperson for Mandate, which represents many of the 100 staff, said it remains concerned for the long-term security of their jobs.
Bill Kelly, divisional organiser with the union, also appealed to Dunnes Stores and receivers Grant Thornton who have charge of the shopping centre to sort out the row over access to Dunnes speedily.
The row centres on Dunnes Stores opening of doors direct from the car park into its outlet, allowing shoppers to bypass other traders in the main mall.
The company shut the branch after the High Court granted an injunction preventing it from continuing to use those doors.
The injunction was obtained by Paul McCann of Grant Thornton, who was appointed by AIB as receiver to run the centre.
Lawyers for the receiver argued the use of the door was a breach of Dunnes' lease obligations and the net effect was that customers could bypass smaller traders in the shopping centre.
Dunnes Stores had opposed the application, and urged the court not to grant the injunction.
