Element Six, formerly De Beers, shocked its staff in July when it announced that manufacturing and distribution would be moved to lower cost locations overseas and 370 of the 450-strong workforce would be made redundant. The company employs over 100 Limerick people, it is understood.

Local management then brokered a deal with the corporation to keep a more streamlined highly-skilled manufacturing base that would see 163 jobs retained, bringing the total workforce up to around 250.

SIPTU and the TEEU said they would not enter conciliation until the company increased the redundancy on offer to workers with the company replying that the whole rescue plan could fail if talks got bogged down on redundancy.

Redundancy has been on the table at LRC hearings in the Castletroy Park Hotel but the Commission, with the agreement of both parties, last week referred the dispute to the Labour Court.

"We welcome the outcome of today's talks at the LRC as a positive and constructive step in our efforts to reach agreement on the sustainability plan, which is about securing a future for our operations at Shannon and an additional 163 jobs," said Element Six Shannon general manager Ken Sullivan.

Redundancy remains a sticking point for unions. While the initial offer has been improved, it falls far short of the eight weeks per year of service agreed in severance with staff only last December. Element Six has said that bargain was struck in different circumstances and it simply "can't afford" to improve the pot of €8 million currently available for redundant staff.

And unions also have difficulties with some elements of the sustainability plan, including changes to shifts, increased workload, health and safety and other terms and conditions to employment.