The Right2Know Campaign intends challenging the Protection of State Information Bill in the Constitutional Court.
"The secrecy Bill remains a threat to our democracy and we will continue our campaign to stop it," the movement, which was born in opposition to the official secrets draft law, said on Wednesday.
"If Parliament fails to introduce the necessary amendments and President [Jacob] Zuma signs it into law, the Right2Know will take the fight to the Constitutional Court."
ANC MPs on the National Council of Provinces (NCOP) ad hoc committee handling the Bill approved a report adopting the legislation, while opposition MPs walked out in protest on Tuesday.
It is scheduled to be debated in the council on Thursday, and is likely to be passed thanks to the ruling party's majority. The Bill will then be sent back to the National Assembly for approval before the president can sign it.
Right2Know said despite last-minute amendments, the Bill still clashed with the constitutional rights to freedom of information and expression and was likely to lead to over-classification.
It criminalised mere possession of secret documents and publication of classified information, even that which was already in the public domain. The group said lawmakers had failed to sufficiently narrow down the definition of national security as the rationale for classification, leaving room for security officials to suppress disclosures in the public interest.
"The secrecy Bill still carries the fingerprints of the securocrats who have remained the 'hidden hand' behind this process from the start." MPs should vote with their conscience and reject the Bill, it said.
The South African National Editors' Forum said the Bill remained a threat to democracy and urged NCOP members to reject it and force a redraft. "We call on members to take this final opportunity to reject it outright, by voting against the Bill.
"By doing so, they can send a clear message that the Protection of State Information Bill must be thoroughly redrafted to ensure that state secrecy is narrowly defined, the powers of bureaucrats and security officials limited, and basic constitutional principles respected."
The South African Chapter of Media Institute of Southern Africa (Misa-SA) appealed to NCOP members to vote against the Bill. "If this is done media freedom — which is no more than the peoples' freedom — will be protected and the government's ability to throw a cloak of secrecy over activities that the public should know about will be curtailed," Misa-SA chairperson, Raymond Louw, said in a statement on Wednesday evening.
One of the Bill's contested features was the power it gave the state security minister, Louw said. "Misa-SA calls on members of the NCOP to show their determination not to be dictated to by a Cabinet minister and go the whole hog by voting against the Bill. This will mean the Bill will have to be redrafted from scratch so that it meets the demands that official secrets should be clearly and narrowly defined … ." – Sapa