The Nelson Mandela Foundation (NMF) has urged that the Protection of Information Bill give judges greater discretion in dealing with secrecy charges.
The foundation, in a 31-page analysis of the draft law, proposes that elements of the original draft tabled in 2008 by the then minister of intelligence, Ronnie Kasrils, should be reintroduced.
The ad hoc committee considering the bill has slowed its work.
It is expected to postpone finalisation until the third session, which begins late next month.
MPs are working on a possible amendment that could allow for appeals against the classification of a specific document to a panel headed by a retired judge.
The foundation, which protects the legacy of the former president, became involved because the bill could have implications for the management of archives.
"The reform of South Africa's antiquated and paranoid information-security law is a necessity," the NMF says.
It stops short of supporting the public interest defence sought by media to allow judges to condone disclosure of official secrets if the public interest outweighs the potential harm.
Instead, it calls for a "harm test" that would allow a judge to impose a sentence related to the harm caused.
Just R20 for the first month. Support independent journalism by subscribing to our digital news package. 
