Around 250 more jobs will be lost at Peugeot-maker PSA's Ellesmere Port plant in England on top of around 400 cuts announced last year, to reduce the plant's output to one shift.
Peugeot acquired British brand Vauxhall last year when it bought General Motors' loss-making European arm.
The move raised fears among unions and lawmakers of job losses and possible plant closures as part of cost-cutting plans.
In October, PSA said it would cut about a quarter of its workforce at the site by the end of 2017 to improve the production facility's competitiveness.
A spokesman said today that the company told representatives of the Unite trade union at a meeting last week that it now needed to go further.
"The company explained that although the initial voluntary separation programme at its Ellesmere Port plant announced in October has been successful, it needs to initiate a further voluntary programme for eligible employees of a further 250," the firm said in a statement.
"The teams are conscious of the need to accelerate the recovery of plant productivity in order to meet the challenges ahead," it said.
The firm will move to a single production shift in April.
Vauxhall, the British arm of the Opel brand sold in the rest of Europe, builds the Astra model at the site.
It is due to decide on whether to renew production this year, seen as a key test of Britain's ability to attract investment as it leaves the European Union.
