More than 200 jobs are being lost at a lens-making factory in Wrexham.
Workers at the Japanese company, Hoya Lens UK , have been told that production is being moved to Thailand.
They were given their 90-day statutory notices on Monday.
The firm makes and supplies ophthalmic lenses to opticians in the UK and Europe.
It has two factories in the Wrexham area, and has invested £20m in them over the last two years. It currently employs 464 people at the sites.
The company says its neighbouring factory, where 220 people are employed, will not be affected.
Economic Development Minister Andrew Davies said he was "deeply concerned" after the news "came as a complete shock".
"The decision to shed these jobs is part of a larger rationalisation exercise designed to develop Hoya's global manufacturing and supply chain capability," he said.
This is a major blow to Wrexham and demonstrates that the manufacturing industry....is still very vulnerable
"The move will allow Wrexham to focus on UK market development - Hoya have long-term plans within this market.
"Unfortunately, [recent] improvements cannot bridge the gap between UK unit cost and that in other parts of the world. "
But Plaid Cymru's north Wales AM Janet Ryder said it was "just the latest in a series of blows to manufacturing in Wrexham", which she said had lost 500 jobs this year.
She called for the government to grant the region lucrative Regional Selective Assistance (RSA) aid by relaxing qualification criteria.
Mr Davies responded that unemployment in the town was "historically low" - having fallen by 26% since 1999 - implying businesses in the region would not be allowed RSA grants.
The assembly government said the Welsh Development Agency, Jobcentre Plus and Careers Wales will help redundant employees find new jobs.
Wrexham Councillor Neil Rogers, who has special responsibility for Economic Development and Regeneration, said he was upset and disappointed due to the impact the job losses would have on Hoya employees and their families.
"We are deeply saddened that we are once again losing high quality, highly skilled and well paid jobs," he said.
"This is a major blow to Wrexham and demonstrates that the manufacturing industry in Wrexham is still very vulnerable.
"With hindsight the loss of 'assisted' area status has not helped us retain business and therefore our focus needs to be on trying to attract and develop new innovative businesses to Wrexham."
He added: "Wrexham is the only authority in the whole of Wales which does not receive 'assisted area' status."
Steve Ellis, the Managing Director of Hoya Lens UK, said work will continue as normal until October when the factory will shut - the formal consultation process begins this Friday.
The job cuts are on top of 500 others announced this year. In April electronic typewriter maker Brother Industries revealed plans to shed 100 jobs in Ruabon.
Further cuts include 46 at Beauforts; 50 at Tetrapak; 35 at Wrexham UK; 30 at European Fine Blanking and 250 at Owens Corning.
Currently unemployment in Wrexham is at 2.4% which is below the national average.