Almost 200 jobs have been placed at risk at a Kingsmill factory in Cardiff under restructuring plans.
Allied Bakeries, which makes the Kingsmill brand, has revealed plans to stop production in the Welsh city.
The group is set to halt bakery production at the Maes-y-Coed Road site as part of a review of its operations after it lost a major own-label contract earlier this year.
Allied Bakeries said it will shift baking to other UK facilities, but plans to continue running its transport logistics depot from the Cardiff site, supplying bakery products and bread across Wales and the South West of England.
It is now consulting with the 360 staff at the site. However, 180 jobs will be cut.
A company spokesman said: "Earlier this year Allied Bakeries announced the loss of a major own-label bakery contract, following which we have undertaken a detailed review of our bakery network to optimise our production capacity, locations and routes to market."
He added: "If these proposals are accepted it will regrettably result in some redundancies and we understand that this announcement will be unsettling for our colleagues in Cardiff.
"If these changes go ahead we will provide support to anyone impacted to help them find a new job, either at another Allied Bakeries' site, or elsewhere in the local community."
The Bakers' Food and Allied Workers' Union said it was a major blow for the bakery workforce and for Wales, given a swathe of recent factory closures in the country, including Ford's decision to shut its plant in Bridgend.
BFAWU general secretary Ronnie Draper said: "It's devastating for Wales if you think about all the things that are going on in Bridgend."
He added: "A lot of this is down to the power of supermarkets - they shift a product from one manufacturer to another without thinking about the consequences on jobs."
Allied Bakeries is owned by Associated British Foods, which also owns high street fashion chain Primark and tea brand Twinings.
