Mandela made a Palestinian state one of his main international causes after becoming President.
Senior Hamas officials on Tuesday joined the family of Nelson Mandela to mark the 10th anniversary of his death and cast the spotlight on the bitter conflict in Gaza.
South Africa has strongly condemned Israel's response to the unprecedented October 7 Hamas attacks that unleashed a war in which thousands have died.
Mandela, who died aged 95 in 2013, made a Palestinian state one of his main international causes when he became South Africa's first black president.
And Hamas representatives were among Palestinians who laid a wreath when the Mandela family paid tribute at a giant statue of the anti-apartheid icon.
Mandela's grandson, national assembly member Mandla Mandela, helped organise a two-day conference on the Palestinian-Israel conflict before the wreath-laying at the Union Buildings.
Basem Naim, a former Hamas health minister in Gaza, and Khaled Qaddoumi, the militant group's representative in Iran, were among Palestinians to visit for the conference and anniversary.
"We were waiting to gain first-hand experience of the daily atrocities that are being carried out in Gaza," Mandla Mandela told national broadcaster SABC.
"It was a real experience for them to be in South Africa and learn from our experience as we had to face one of the most brutal apartheid regimes on the continent and we were able to defeat it."
He said his grandfather considered a Palestinian state "the great moral issue of our time" and added: "We are carrying on where he left off."
Mandla Mandela is part of the ruling African National Congress which last month backed a national assembly motion calling for the closure of the Israeli embassy and for a suspension of diplomatic ties in protest at the war.
South Africa has also officially called on the International Criminal Court to investigate what President Cyril Ramaphosa has called Israel's "war crimes" in Gaza.
Israel says 1,200 people were killed when Hamas fighters crossed the border on October 7. The Hamas government says nearly 16,000 people have died in Israel's military assault on Gaza since.
Israel, which has rejected comparisons between its conflict and apartheid, did not send a senior leader to Mandela's funeral in 2013.
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