The South African Federation of Trade Unions (SAFTU) has called for a boycott of produce from a wine farm in Grabouw in the Overberg.
SAFTU General Secretary Zwelinzima Vavi made the call during a march against the alleged discrimination of black workers at Oak Valley Farm.
The matter has been reported to the SA Human Rights Commission.
The protesters, who are mainly seasonal workers, have been on a labour strike for three weeks demanding a daily wage of R250, an end to labour brokering and for the scrapping of single man hostels.
Vavi handed over a memorandum to the local police station, a representative of an agriculture body and to Oak Valley Farm management.
Farm representatives have seven days to respond to the workers demands.