The Nelson Mandela Foundation has hit back at disparaging remarks attributed to US President Donald Trump involving the late South African statesman.

In a short statement on Monday, the foundation said it did not believe leaders who conducted themselves in the way Trump did were "in a position to offer authoritative commentary on the life and work of Madiba".

"Reflecting on leadership, Madiba once said: 'A good leader can engage in a debate frankly and thoroughly, knowing that at the end he and the other side must be closer, and thus emerge stronger. You don't have that idea when you are arrogant, superficial, and uninformed'.

"We would recommend these words to Mr Trump for consideration."

Comments were attributed to the US president about African leaders and former South African president Nelson Mandela in particular, in a book by Michael Cohen titled Disloyal: A Memoir.

Cohen, who previously served as an attorney for Trump, alleges in his book that Trump had a "low opinion of all black folks", The Washington Post reported.

According to the publication, Cohen wrote that after Mandela died, Trump allegedly said he did not think Mandela "was a real leader - not the kind he respected".

Cohen further writes that Trump praised the apartheid-era rule in South Africa, apparently saying Mandela "f---ed the whole country up. Now it's a s---hole. F--- Mandela. He was no leader".