Harrods could be closed by a strike over changes to staff pensions and working hours, according to newspaper reports.
Owner Mohamed Al Fayed has told staff the London department store will open for an extra hour each day from 3 April.
The move, which follows the axing of their final-salary pension scheme, has angered employees.
Union Amicus said the firm was “rubbing salt into the wounds” by expecting staff to work longer while slashing their pensions.
Al Fayed’s plan was revealed in a letter to staff leaked to the Mirror.
He wrote: “As a business we have always listened and reacted to the ever-changing needs of our customers and with this in mind we have made a decision to open until 8pm, Monday to Saturday. I am once again asking for your support and co-operation in making this possible.”
Earlier this month Harrods announced plans to shut its final salary pension scheme to new and existing members from 6 April.