"It is a priority for the Shoprite Group to resolve the matters that have been discussed over a period of time through the appropriate channels in the interest of all our employees‚ as well as our customers‚" the supermarket chain said in a statement.

"The Group is disappointed that customers may not experience the service the Group would like to deliver in the height of the Festive Season‚ but it respects the rights of employees to protest in a peaceful and lawful manner.

"We are confident that we will be able to keep our customers’ shopping experiences as pleasant as possible in the circumstances and thank them in advance for their understanding. Contingency plans are in place to keep stores open and trading as normal as possible."

More than 30‚000 workers are expected to take part in the protected strike on Friday‚ according to the South African Commercial‚ Catering and Allied Workers' Union (Saccawu) and the Congress of South African Trade Unions (Cosatu).

The workers are demanding a reversal of changes to working hours‚ the reinstatement of Sandton Checkers employees who were dismissed for protesting against the changes‚ safe transport for night-shift staff and a guaranteed number of minimum working hours for part-time workers.