Supermarket chain Kwik Save is to reopen 20 of the 79 stores it closed last month, following talks with financial backers on the future of the business.
Workers who were laid off at the end of May have been sent letters asking for volunteers to return to their old jobs.
Kwik Save said it planned to reopen the 20 supermarkets on Wednesday. These include stores at Wolverhampton, West Smethwick, Coventry and Nuneaton.
Around 700 workers lost their jobs when the company announced on May 29 that it was closing around a third of its chain in an attempt to secure the future of the business.
A spokesman for the shopworkers’ union Usdaw said: "We have written to the company asking some tough questions about the long-term job security for our members.
"We have also raised questions about the supply chain to make sure the stores which are reopening are properly stocked."
The union said it will support any of its members who decide to return to work but they will also back anyone who decides to take up their redundancy payment, due to be paid on June 21.
Kwik Save said last month the decision to close so many stores had been "difficult" but said it was necessary to enable the business to succeed.