Harrods restaurant employees are planning on demonstrating against a service charge system in place at the department store that retains the majority of money contributed to the tronc.
The United Voices of the World union (UVW) claims that Harrods retains up to 75% of the service charge collected at the 16 cafes and restaurants in the landmark store.
A spokesperson confirmed to the Guardian that the company shared service through the tronc system, adding that the detail of the system was now under review.
They said: "Harrods is taking steps to improve the current system through which it distributes its service charge, to ensure it best serves our employees and is completing a detailed review into the existing scheme.
"As this is an ongoing review, we are unable to provide further details on the distribution. However, employees will be informed of the details of the new system as soon as the review is complete."
The UVW union said that the system reduces pay owed to each of the 483 kitchen and waiting staff by up to £5,000 a year.
Petros Elia, the UVW general secretary, said: "Customers expect the service charge to go to staff and that's where it should go. If Harrods feels the need to retain a percentage they should explain why."