The Paris-based Reporters without Borders has warned Jacob Zuma that he was setting a bad example for African dictators with his defamation lawsuit against the media.
"A successful lawsuit by you would give a blank cheque to Africa's authoritarian regimes, which would use your example to attack their own press," the organisation said on Tuesday, quoted in an open letter it had written to the former deputy president.
Reporters without Borders defends journalists facing prosecution for doing their work and fights to reduce the use of censorship and opposes laws designed to restrict press freedom, according to its web site.
It has a network of over 100 correspondents around the world.
Secretary-General Robert Menard said his organisation, based in France, had told Zuma that should the mechanisms that ensure pluralism and free expression seize up in South Africa, it would put the entire region's press in danger.
This was because South Africa was seen as "the peacemaker and development model for all of southern Africa", Menard added.
Zuma is suing media owners, publishers, editors, reporters, cartoonists and newspapers over reports during his recent rape trial. He was found not guilty.
"The exorbitant amounts in damages that you are demanding from the media seem more like an attempt to intimidate them than the response of an injured party," read an open letter to Zuma from the organisation.
"This approach will only encourage the privately-owned press to turn their sights on you, and will in no way help you obtain reparation for any wrong you may have been done."
Menard pointed out to Zuma that the independent press used its right to free expression but also gave him the right of reply.
"We urge you to support the independent press by engaging it in a dialogue rather than brandishing the threat - one that is out of all proportion for a political leader at the national level - of financial and judicial penalties that would prove fatal for all the media concerned."
The letter added: "Reporters Without Borders is amazed by the manner in which you have demanded damages from the newspapers The Star, The Citizen, Sunday Sun, Sunday Times, Sunday Independent, Sunday World and Rapport, from Radio Highveld Stereo and from cartoonist Jonathan Shapiro, who uses the pen name Zapiro." - Sapa