Seven hundred jobs are at risk as Caterpillar considers a restructuring of its Northern Ireland operations.
The company announced on Thursday it was opening a consultation process with production, support and management in its electric power division operations
Overall the workforce could be reduced by almost half. The company employs around 1,600 people at sites in Belfast and Larne.
In a statement, the company said its move supports the company’s ongoing plans to "better utilise existing capacity and improve cost competitiveness". It said Brexit or the coronavirus pandemic or end of the furlough scheme played no part in its decision making but was about making the business more efficient.
UUP MLA John Stewart called for the Economy Minister Diane Dodds to intervene in order to protect jobs.
"It is vital that the Economy Minister Diane Dodds and Invest NI meet with senior management now to see what can be done to mitigate the losses. It is also essential that the Council’s Manufacturing Task Force steps up to work with Caterpillar employees to provide support and signposting to new training opportunities."
The transition period is set to begin in the new year and could last for up to 18 months.
"The contemplated changes would predominantly affect operations in Larne as the plan would include a relocation of a portion of that work and the relocation of some engineering activities to other Caterpillar facilities," the company said.
"The company is also considering the sale of the Millennium offices building located in the Springvale Business Park, relocating the remaining employees to the Larne facility.
"Today’s communication is not a closure of Caterpillar’s operations in Northern Ireland, but a strategic evaluation to make a more efficient use of our manufacturing footprint."
In a statement Economy Minister Diane Dodds said the announcement was "hugely disappointing".
"The situation has arisen as a result of a decision made by Caterpillar at corporate level. The announcement and potential job losses are not directly related to Brexit or Covid-19," she said.
"The company has clearly stated their announcement is not a closure announcement. I have confidence in Northern Ireland’s capability and that the Caterpillar operation will continue to be a key contributor to the manufacturing and engineering base in Northern Ireland.
"Since 2000 Caterpillar has invested £135million in Northern Ireland and been a major contributor to Northern Ireland’s reputation for manufacturing and engineering excellence.
"Invest NI will work with the Caterpillar Senior Management Team to mitigate potential impact on the Northern Ireland operation.
"The Department’s Careers Service is available to support those potentially impacted by offering free professional and impartial careers information, advice and guidance tailored to individual needs and helping people to explore future training and employment opportunities."
Joe Creed, Caterpillar vice president of the electric power division added: "We recognise that what we are considering is difficult for our employees, their families and the community. We do not take these contemplations lightly, however, we must plan for future business needs to be competitive.
"Consultation on intended actions will occur with the appropriate representative groups for the hourly and salaried workforce.
"During the consultation process, Caterpillar is committed to ongoing communication with employees to provide more information on the proposed changes. If finalised, the transition could begin this year and would be expected to be completed in the next 12 to 18 months.
"The company also has the intention to provide severance packages to redundant employees and consider outplacement services from appropriate agencies to ensure they have support during this transition."