An official memorial service will be held for the late struggle stalwart Ahmed Kathrada, the Presidency said on Tuesday.

"The president has instructed that the national flag fly at half-mast at every station in the country from today, 28 March until the evening of the official memorial service," it said in a statement.

Kathrada died on Tuesday morning.

Zuma sent his condolences to Kathrada's wife, former minister of public enterprises Barbara Hogan, the Kathrada family and his political home the African National Congress, "which Uncle Kathy served selflessly throughout his adult life".

"The family has requested a private funeral ceremony and the details will be announced by the Ahmed Kathrada Foundation," the Presidency said.

"An official memorial service will be organised and the details will be announced in due course.

Deputy President Cyril Ramaphosa will lead the send-off of the much-loved stalwart within government."