A European legal campaign is being launched to have Waterford Crystal glass only made in Waterford.
The Unite trade union has announced plans for a test case to force the current owners of Waterford Crystal to repatriate manufacturing of the brand to the city.
Waterford Crystal closed in 2009 with the loss of 600 skilled jobs.
The brand name was bought by KPS Capital Partners, a US private equity company with $2.5bn (€1.9bn) worth of assets.
Some crystal items are again being made in Waterford but the vast majority of manufacturing has moved away from Ireland.
The brand is still sold under the original Waterford trademark and the union is now going to challenge the use of the trademark on glass not produced in Waterford.
It said there is significant legal and commercial precedent for a successful action against the making of products in other regions, such as Champagne in France and Parma ham in Italy.
The union would be taking the test case to The Registry of Trade Marks in Alicante in Spain and then possibly to the European Courts of Justice.
KPS Capital Partners says its subsidiary WWRD (Waterford Wedgewood Royal Doulton) has demonstrated an ongoing commitment to bring manufacturing back to the city of Waterford.
WWRD was formed in March 2009, two months after the receiver to Waterford Wedgewood plc closed down the facility in Waterford with the loss of 600 jobs.
In June 2010 KPS opened the House of Waterford Crystal in the centre of Waterford city, creating over 120 jobs.
KPS says the House of Waterford Crystal was the result of a huge amount of hard work led by WWRD and Waterford City Council, and a working group which included a wide range of local stakeholders, including Unite.
A company spokesperson says WWRD is committed to manufacturing in Waterford city and they always welcome constructive dialogue with Unite.