Right2Know have staged a number of protests and marches to fight the secrecy Bill.
Speaking during a protest march in Pretoria on Friday, Right2Know (R2K) campaign Gauteng spokesperson Dale McKinley said the "flawed" Bill had to be withdrawn.
"The Bill before Parliament is still flawed and has many problems. There are several reasons [for opposing the Bill], but the main one is the lack of a public interest defence clause and lack of protection for whistle-blowers," he said.
Few people gathered in central Pretoria for the march to the Union Buildings. McKinley said the low attendance was caused by "transport issues" in bringing people from the townships.
"There are huge … criminal consequences for possessing and exposing information; it is a very draconian piece of legislation. It will take us back to a secretive state and I don't think any South African wants that," said McKinley.
"It is International Right To Know Day across the world today, and we are going to say to the presidency, 'take the Bill back and re-consider'. We are marching to defend freedom of expression."
He said support for calls to halt the Bill was widespread.
"The support has been cutting across racial and social class lines. The collective pressure has been working so far. We have seen communities, unions, churches opposing the Bill.
"The vast majority of South Africans are against the Bill and want to defend their right to freedom of access to information," said McKinley.
A statement issued by R2K later on Friday called on government to stick to its promise to set up a whistleblower protection fund. It said whistleblowers already suspended or dismissed for speaking out against abuse of power must be reinstated.
The Bill must be referred to the Constitutional Court before being signed into law, the group said.
On Wednesday this week, the DA Abroad said it would lead a protest on Friday by South Africans living in London against the Bill.
Global chairperson Ludre Stevens said the demonstration at the South African High Commission was a bid to draw attention to the "dangerous" consequences that would follow if Parliament were to pass the current draft of the Bill.
"If this secrecy bill were to be enacted in its current form, we might never be able to access the truth of what [really] happened at the Marikana tragedy, or get to the bottom of the controversial arms deal," he said.
The Bill has been rewritten extensively but critics say many problem areas remain, notably the lack of a public interest defence for those who publish state secrets to reveal wrongdoing.
It is expected to be adopted by the National Council of Provinces next month, and then referred back to the National Assembly before it is signed into law.
The ANC has indicated it is not prepared to make further concessions on the Bill. – Sapa