Up to 150 jobs are believed to be at risk at the Element Six facility in the Shannon Industrial Estate.
Workers have been asked to attend a briefing by senior management at the plant this morning.
There are fears that the international diamond manufacturer is seeking up to 150 redundancies.
The multinational - formerly known as De Beers - already cut its 620-strong workforce by 120 through voluntary redundancies last December.
However, there is concern that the firm won't be able to offer the same severance package this time around.