Adelaide Frances Tambo, widow of former ANC president Oliver Tambo, died on Wednesday night, the African National Congress confirmed.
"It is with deep regret and a profound sense of loss that the African National Congress has learnt of the death this evening of Adelaide Tambo, widow of the late ANC president Oliver Tambo and an outstanding stalwart of our movement," said ANC spokesperson Smuts Ngonyama.
Ngonyama said Tambo collapsed at her home in Johannesburg on Wednesday evening.
"The ANC joins all South Africans in mourning the loss of a true heroine of our nation, a daughter of our soil who dedicated her life to the freedom of our people.
"Together with all South Africans, the ANC extends heartfelt sympathies and condolences to the Tambo family on this great loss."
He said that Tambo's strength, compassion and determination served as inspiration to generations of freedom fighters throughout "the most difficult times of the struggle for democracy".
Tambo is survived by three children, Tembi, Dali and Tselane and several grandchildren. - Sapa