Investigative journalist Jacques Pauw stands by the allegations contained in his recently-released book and says he is prepared to seek punitive costs orders against that State Security Agency (SSA) if it approaches the courts for an interdict against him.
Such orders will also be sought against "individuals within the agency who instructed you to bring such an application".
Pauw says that allegations of financial mismanagement at the SSA, contained in his book The President's Keepers are true and "of undeniable public interest".
The first print run sold out on the day of the release and more are being printed.
Last week, the SSA sent a cease and desist letter to Pauw and NB Publishers, claiming that the content of the book violated the Intelligence Services Act.
The agency threatened to approach the court for an interdict to prevent further distribution, publishing or promotion if the book was not withdrawn from store shelves.
It also threatened criminal charges. But Pauw was not fazed.
Instead, he and the book publishers hit back on Monday, issuing a letter through lawyer Willem de Klerk, in which they described as "incongruous" the agency's demand for a retraction.
"Your generalised statement that the book is 'replete with inaccuracies' is not backed up by a single reference to any specific statement in the book that is alleged to be inaccurate," the letter pointed out.
'Evidence of criminality'
It added that it was unclear how the agency reconciled an allegation of falsity with an alleged violation of statutory provisions on the other.
"Exposing evidence of criminality within the State Security Agency cannot compromise the agency's legitimate operations or the security of the state. Publication of the information contained in the book does not violate the 'relevant intelligence statutes' as you allege," the letter read further.
The book had been available for more than two weeks and thousands of copies have already been sold, both in stores and digitally.
Some of its contents have also been divulged in extensive media reports and on social media.
An urgent application to prevent further distribution would, therefore, serve no purpose, the letter said.
"Your client waited for the best part of a week before making its demand, and then set a five-day deadline for response," they added.
Pauw and the publishers referred to the agency's intention to bring an application "without further notice".
This, they countered, was unlawful.
They requested that their lawyer's letter be put before the court if such an application was lodged.