Late anti-apartheid struggle icon Winnie Madikizela-Mandela was a unifier who became a face of the struggles faced by black women all the world, Deputy President David Mabuza said as he paid tribute to the woman dubbed the 'Mother of the Nation' on Wednesday.

"Her activism cuts across the distinctions of gender, race and class. She was committed to the attainment of all human rights for all people. Her only preoccupation was to serve humanity in its totality," he said as he addressed mourners at the memorial service for former president Nelson Mandela's second wife held at Orlando Stadium, Soweto.

"She triumphed to lead a life of reconciliation, and the reconstruction and renewal of our society."

Madikizela-Mandela, who died in Johannesburg aged 81, was one of "those indestructible rocks that apartheid struck when it sought to denigrate,abuse and oppress women in our society", said Mabuza.

He added that Madikizela-Mandela, who qualified as a medical social worker 60 years ago at the Jan Hofmeyer School of Social Work, epitomised her profession in the way she lived her life through the height of apartheid. 

"The need for more social workers of her calibre who will place the betterment of our society ahead of their personal well-being remains a necessity."