Up to 1,200 Tesco call centre jobs could be at risk as the supermarket giant plans to close its site in Cardiff, a union has claimed.
USDAW said staff in the city had been briefed on a plan which could see its customer engagement centre, in Heath, shut in February 2018.
The operation could instead be moved to Dundee in Scotland, where 200 jobs would be created.
The union said it was "devastating news". Tesco has been asked to comment.
Nick Ireland, USDAW divisional officer says: "Tesco's Cardiff call centre staff are understandably shocked by the announcement of the company's planned closure, they are being briefed by managers this afternoon.
"USDAW reps and officials are providing support to our members at this difficult time. This is clearly devastating news for our members and will have a wider impact on south Wales, as so many jobs are potentially lost to our local economy."
He added: "Our priorities are to keep as many members as possible in employment, whether that is with Tesco or other local employers, and to get the best possible deal for our members. In the meantime we are providing the help, advice and support USDAW members need through this process."
He said the union would enter consultation talks with Tesco to look at the business case for the proposed closure.