Twenty-eight female guards were unfairly dismissed by a security company because the client‚ Metrora.
Nelson Mandela will return to South Africa from Mozambique to convey his condolences and offer support to the Tambo family.
Mandela said Adelaide Tambo was an exceptional woman who was loyal to her family and the country.
"She was OR's [Oliver Tambo's] life-long partner, caring supporter, confidante and struggle comrade.
"We pay tribute to my close friend, and to a life dedicated to freedom and service." - Sapa