President Cyril Ramaphosa has denied claims that he was a spy and worked with apartheid authorities in the early 1970s against his fellow comrades.

Speaking out publicly for the first time after Cope leader Mosiuoa Lekota made shocking allegations on Wednesday that Ramaphosa "sold out" his comrades when he was incarcerated, Ramaphosa said he stood his ground and refused to do so.

"My arrest was quite dramatic. They [apartheid police] started interrogating me viciously and the issue was that they wanted me to give evidence against accused number one, Seth Cooper, accused number two, Muntu Myeza, and Terror Lekota, accused number three, [among] many others.

"I refused. They thought they would use my dad to put pressure on me to agree to become a state witness and I said I will not do it," said Ramaphosa.

Ramaphosa's father was a police sergeant at the time.

The president said that the apartheid police tried to use his father to convince him to become a state witness, but he was having none of it.

"[I said] 'Dad, I am not going to do it. I will never betray the comrades that I was working with and if I did, where will I go and live thereafter'? I refused," said Ramaphosa to a round of applause.