Prime Minister Tony Blair has told MPs his government will help 650 staff made redundant at two Sony factories in south Wales.
Sony announced on Wednesday the closure of its Bridgend plant and the ending of production of cathode ray tube televisions at its nearby Pencoed site.
Sony blamed the demand for new flat screen televisions for the job losses.
Political parties in Wales expressed shock as Mr Blair offered to meet local MP Huw Irranca-Davies over the cuts.
Mr Blair told the Commons: "It is our responsibility to put in place a proper package of support and help."
He added: "We are drawing jobs in, but... the changing way the market is working is meaning that it's very hard for people to remain secure in the jobs they have, even with excellent companies like Sony."
Around 300 jobs will remain at Pencoed with the continued production of digital cameras and provision of customer support at the site.
Bridgend Assembly Member Carwyn Jones described the announcement as "devastating news" for the workers.
"Sony is one of the biggest employers in Bridgend and I am extremely disappointed that the company has decided to make these cuts.
"It is a body blow to the whole economy of Bridgend."
"I am urgently seeking to meet with the trade unions and management at Sony to discuss the matter and find the best possible outcome for the workers, their families and the local area."
Welsh Economic Development Minister Andrew Davies said his first thoughts are with those employed there and those facing redundancy.
Mr Blair pledged to support the Sony workers
"We will do everything we can to help them either to seek alternative employment or if necessary to have retraining," he said.
"There is a silver lining in this in that Sony will retain 300 jobs at its Pencoed plant.
"This is a commercial decision by Sony because at the Bridgend plant they were making an old form of technology - the cathode ray tube TVs for which there was no demand.
"It's not good news, but we have faced significant redundancies in the past and we have managed those successfully."
'High quality jobs'
Wales TUC general secretary Felicity Williams said: "The Wales TUC and trade unions in Wales will keep up our pressure on government in Westminster and Cardiff Bay to do more to protect our rapidly disappearing manufacturing industry."
Plaid Cymru AM Janet Davies, who sits on the assembly's economic development committee, described the job losses as a "real setback".
She said: "These jobs were of high quality and were important to the local economy."
Conservative AM Alun Cairns said the job losses were a blow for the Welsh economy.
He said: "Sony has a reputation for paying good salaries to a highly skilled and highly trained workforce.
"It is sad that the current climate has meant that companies such as Sony have found it difficult to operate in Wales and that the meltdown in manufacturing in south Wales is continuing."
Extending her sympathies to the workers, Welsh Liberal Democrat economic development spokesperson took a swipe at Economic Development Minister Andrew Davies.
"The last time AMs discussed job losses at Sony the Minister claimed he had set up a task force to draw up a plan for manufacturing, yet it is difficult to point to any actions that have helped," she said.
"He pledged to visit Sony in Japan, yet today he has admitted he never made the trip. We have almost 16,000 fewer manufacturing jobs than we did in 2001."