Around 500 jobs in the UK are in jeopardy after an automotive and industrial company announced plans to close down assets in light of "uncertainty surrounding Brexit".
The Schaeffler factories in Llanelli and Plymouth are scheduled for closure. The company proposes to relocate production to plants outside the UK.
A 45-day consultation on the plans has started.
There are 220 employees at Llanelli's plant and 350 employees at the Plymouth plant.
Llanelli's MP Nia Griffith described her "big shock".
"The company has been a major employer in the region for many years," she said.
"I'm obviously concerned about the impact on surrounding families … and the potential impact on other local businesses.
"It's important to try to offer the company all the help to convince them to change their minds."
She said local congregation member Lee Waters has already spoken with Welsh economics minister Ken Skates AM to see what's possible.
"Meeting the company is important as a next step, which reiterates the need for a clear Brexit plan to provide security for companies and employers and end insecurity," she added.
Councilor Deryk Cundy, representing Bynea in Llanelli, said the loss of "well-paid" jobs would be a major blow.
"It will also affect Carmarthenshire and others, and we need to form a task force. [We need] to persuade Schaeffler to reconsider her decision, "he said.
Greig Littlefair, Managing Director of Schaeffler UK, said the company wanted "transparent and fair discussions with the employees concerned".
Schaeffler, which employs more than 1,000 people at five locations in the United Kingdom, will not close its largest plant in Sheffield.
It is expected that the restructuring of the UK will take up to two years.
Jürgen Ziegler, Regional CEO Europe at Schaeffler, said: "Brexit is not the deciding factor in our decisions for the UK market, but the need to plan various complex scenarios has moved forward.
"However, we remain determined to maintain certain activities in the UK, a country that will continue to be important to us."
The closures are part of the company's Agenda 4 plus One restructuring plan, which looks at the strategic and economic competitiveness and long-term sustainability of the assets.