Some 70 workers in Dublin and Cork are to be made redundant while a further 240 jobs are under threat, following separate announcements yesterday.
The 70 job losses have been confirmed for Alcatel-Lucent which employs 260 people in Ireland. The redundancies will be spread across the company's plants in Blanchardstown and Citywest in Dublin and in Cork city.
The company, which provides hardware and software to the telecommunications industry, is to shed 12,500 of its 88,000 staff worldwide. It is hoping to save €1.7 billion over three years as a result of the worldwide job losses.
The moves follows the merger of rival companies, Alcatel and Lucent, last December in a deal worth an estimated €8.5 billion.
A company statement said: "The forced reductions reflect duplications in positions and rationalisations in the product and solution portfolio, as well as ongoing cost efficiency efforts."
Meanwhile, 100 workers at Zomax's plant at Santry in north Dublin were warned yesterday that their jobs could go because a major contract is not being renewed. Zomax, an American multinational employing 255 workers in Santry and Blanchardstown, confirmed to its workforce yesterday that some staff would be put on protective notice.
Zomax is involved in the manufacture and distribution of products such as CDs and printing materials, which are outsourced by other multinationals.
The potential job cuts relate to only to its Santry operation.
Serious concerns have also been expressed about the future of 140 jobs at the Erin Foods plant in Thurles, Co Tipperary.
Erin's parent company, Premier Foods, has been forced to put the factory on the market after a €1.78 million takeover of RHM Foods, the manufacturers of Bisto gravy.
The merger can proceed only if Premier Foods sells on the Erin brand, a requirement that has led to serious job worries in a town that has already been hit by closures in recent years.
North Tipperary Oireachtas members and local political representatives met company management yesterday.