"Mr Mbeki, who spoke to Mr. Kasrils immediately upon learning of the tragic news, recalled Mrs. Kasrils' role in the struggle against apartheid and her steadfast commitment to the building of a non-racial, non-sexist and democratic South Africa post-1994," Mbeki's spokesman Mukoni Ratshitanga said in a statement.

The Independent Online website reported that she died aged 73 on Sunday after suffering a stroke.

It quoted Ronnie Kasrils as saying she collapsed at Constantiaberg Medi-Clinic in Cape Town.

The couple would have celebrated their 45th wedding anniversary next month - the "most wonderful, happy marriage", he said, adding that she did "some fantastic things" in her political work.

Mbeki said: "Comrade Eleanor's passing is not only tragic for Comrade Ronnie and his family. It is a tragedy for all of us who fought for freedom side by side with her.

"Sadly, yet another combatant in the noble army of freedom fighters has fallen."

Eleanor Kasrils was born in 1936 and joined the Congress of Democrats in 1960 after the Sharpeville massacre.

She participated in Umkhonto we Sizwe activities in Durban and was arrested in 1963 and went in exile with Ronnie Kasrils in the same year after escaping from custody.

She did work for the African National Congress in Tanzania and Britain and worked for the late ANC President Oliver Tambo from 1990 until his death in 1993 when she returned to South Africa.

Eleanor is survived by her husband, daughter Bridgette and sons Andrew and Christopher.