The 89-year-old politician died in the early hours of the morning following a lengthy illness, ruling party spokesperson Zizi Kodwa said in a statement.
"The African National Congress sends its deepest condolences to Mama Ruth Mompati’s family and friends. We thank them for having borrowed us this icon of the struggle of liberation of the South African people," said Kodwa.
"The ANC and South Africa as a whole has lost a towering giant and a mother to countless generations of activists. May her soul rest in everlasting peace knowing that her role in building our country’s future will never be forgotten; as a people we owe it to her and generations before that our vision of a united, democratic, non-racial, non-sexist and prosperous society comes to pass."
President Jacob Zuma said Mompati's absence would be felt.
"The whole nation is mourning, in particular those who worked with Mme Ruth from exile to Parliament and various structures of both the ANC and government," he said.
"We feel an immense void."
Mompati had joined the struggle when she was a young woman and continued to serve her country until very last days.
She had a huge legacy within the political sphere having worked beside the late former president Nelson Mandela and Oliver Tambo in their law practice between 1953 and 1961.
She joined the ANC in 1954 and was elected to the National Executive Committee of the Women's League.
She was involved in the Defiance Campaign and went on to be a founding member of the Federation of SA Women.
"She was later one of the leaders of the historic women’s march on the 9th August 1956," Kodwa said.
"She went into exile in 1962 where she underwent military training and held office as secretary and head of the women’s section of the ANC in Tanzania.
"From 1966 to 1973, Mompati remained a member of the ANC’s National Executive Committee. During this time, she also formed part of the president’s office of the ANC also later heading ANC’s Board of Religious Affairs."
Between 1981 and 1982, Mompati served as the chief representative of the ANC in the United Kingdom. She became part of the delegation that opened talks with the South African government at Groote Schuur in 1990.
One of her many career highlights also included addressing the United Nations Special Committee against apartheid in New York in 1992.
She spoke on the subject of women.
The day was then declared an International Day of Solidarity with Women in South Africa.
Mompati went on to serve as a Member of Parliament in 1994. Between 1996 and 2000, she was the country's ambassador to Switzerland.
Upon her return she became the mayor of Vryburg in the North West province and later served as an Executive Member of Umkontho WeSizwe Veteran’s Association.
"She leaves behind a proud legacy of steadfastness, resilience and selfness for her exceptional and outstanding contribution and sacrifice to the liberation struggle," said Kodwa.
The Congress of the People also had praises for the late ANC stalwart.
Cope leader, Mosiuoa Lekota described her "a paragon of selflessness and virtue".
He likened her to Mandela.
"Ruth was a mother, wife, friend, teacher, activist, warrior, negotiator, MP, diplomat, scholar, mayor and a bastion of morality. She was the complete human being," said Lekota.
"A year after the death of the great Nelson Mandela she asked publicly what she, Ruth Mompati, had done, what we had done, to move the struggle forward to achieve a better life for our people. This says all we need to say about her."
Lekota said his party would keep Mompati's legacy alive.
He sent his condolences to Mompati's family.
Newswire ID: 3092
File photo: Gallo Images
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