Two organisations have written open letters to the Nelson Mandela Foundation to ask it to withdraw its invitation to former US president Barack Obama to deliver the annual lecture on July 17.
The Nelson Mandela Annual Lecture Series invites prominent people to drive debate on significant social issues.
Former speakers include former US president Bill Clinton, Archbishop Emeritus Desmond Tutu and Microsoft founder Bill Gates.
The lecture series is an important event on the foundation's calendar and it encourages people to enter into dialogue – often about difficult subjects – to address the challenges society currently faces.
Feroze Boda, spokesperson for CAGE Africa - an organisation that advocates against the injustices of the War on Terror - believes that Obama's principles are contrary to those of Nelson Mandela.
"Numerous first-person accounts and reports are evidence that Obama and his supporters have cultivated a new kind of colonialism in the name of the 'War on Terror', spreading fear, violence and destruction in particular among Muslim communities, through rubber-stamping over 100 military actions a day throughout Africa, and many more in the Middle East," he said.
"US foreign policy has left destruction, division and suffering in its wake, and led to the rise of violent groups."
Palestine Solidarity Alliance spokesperson Naazim Adam said that the decision to invite Obama was a disappointment.
"The foundation is granting Barack Obama a platform to legitimatise a narrative about his legacy that obscures the reality that under his presidency, there was continuity and an increase in American military violence across the world," Adam said.
He referred to the "thousands of civilian casualties" in Somalia, Pakistan, Afghanistan and Syria that continued under Obama's presidency.
"Why should the Nelson Mandela Foundation allow Obama to be associated with the legacy of Nelson Mandela's years of activism, imprisonment and struggle against an apartheid regime as part of his own legacy doctrine?" Adam asked.
Nelson Mandela Foundation chairperson Professor Njabulo Ndebele defended the decision to invite Obama saying that "Madiba had great respect for President Obama".
"In an era defined by worsening tensions between people, in which the spectre of exclusion and intolerance across the world seems to become normalised, the messages of President Obama, like those of Madiba, must be given space," Ndebele said.
"Furthermore, the foundation's key focus areas, including the eradication of poverty and inequality and the dismantling of anti-black racism, are causes that are close to the heart of President Obama. His historic election as the first black president of the United States does have resonance in South Africa, as do many of his pro-poor policies, such as universal healthcare."
He added that, although the foundation will not withdraw its invitation, he welcomed continued engagement with both organisations.