Asda has been forced to trim its workforce due to lower footfall in stores, putting hundreds of jobs at risk.
The supermarket has identified 18 supermarkets which are overstaffed, and started a consultation with 3,257 staff members in those stores yesterday.
The growth of online retail and the increase in automation at checkouts has reduced Asda's requirement for shop-floor staff, and the grocer is looking to redistribute workers into areas of the business with greater need.
However, it is thought that hundreds of staff will lose their jobs, or be forced to work for fewer hours.
The Walmart-owned grocer is also consulting with staff in a further 59 stores to look at moving workers to where they are needed most.
Asda posted dismal annual results last week; pre-tax profits fell 19 per cent to £791.7m. Sales fell from £22.3bn to £21.6bn. Aside from dealing with the switch to online retailing, the firm has faced tough competition from the discounters Aldi and Lidl.
An Asda spokesperson said: "It is common practice for a supermarket to need to make changes to hours based on the changing shopping habits of customers, and as ever we'll work with our colleagues to try to find the right way to ensure we have the right people, in the right place at the right time for our customers."
"We understand that any conversations about change are unsettling but it is always our upmost priority to find alternative roles or working patterns for impacted colleagues."