Johannesburg - EFF leader Julius Malema needs psychological help, the ANC Youth League (ANCYL) said on Monday.
This was in reaction to Malema's statements during a visit to the UK last week.
"The attacks on [former] president Nelson Mandela, the father of the nation, were most unfortunate, but considering the state of mind of the man who makes them, the nation should not be worried, but should raise concern on how many people believe in this fellow given his views," the ANCYL said in a statement.
The organisation said Mandela's stature and legacy spoke for itself, not only in South Africa, but globally and did not deserve such unwarranted remarks from anyone "let alone a creature of Malema's stature".
Malema told the Oxford Union in the UK Mandela had turned his back on parts of the revolution after being released from prison.
"The deviation from the Freedom Charter was the beginning of the selling out of the revolution. But why did Nelson Mandela sell out the Freedom Charter? When Mandela returned from prison, he got separated with Winnie Mandela and went to stay in a house of the rich white men... he was looked after by the Oppenheimers," he said.
"Nelson Mandela used to attend the club meetings of those white men who owned the South African economy at the time."
Malema's comments were in response to a question on whether Mandela betrayed the people of South Africa in exchange for political power.
The ANCYL accused Malema of being a hypocrite and someone who just wanted to show off.
It called on people to ignore and isolate Malema.
Malema's comments have also raised the ire of the late former president's grandson Mandla Mandela, ANC deputy secretary general Jessie Duarte and the Congress of the People (Cope).