Former president Nelson Mandela did not write the foreword to the book Straight Speaking for Africa by Denis Sassou Nguesso, the President of the Republic of Congo, the Nelson Mandela Foundation said on Tuesday.

"This is a false claim. Mr Mandela has neither read the book nor written a foreword for it," the foundation said in a statement.

"We condemn this brazen abuse of Mr Mandela's name. We will be taking appropriate action."

The entry for the book on the allbookstores.com website reads: "Straight Speaking for Africa by Nelson Mandela (Foreword By), Denis Sassou Nguesso Paperback ? September 2009 List price: $19.95."

The book is published by Michel Lafon and Africa World Press.

"Mr Mandela is still overwhelmed by requests to write book forewords. A year ago he indicated he will no longer be agreeing to such requests," the foundation's acting chief executive Verne Harris said.

Africa World Press could not be reached for comment.