ANC majority in parliament pushed through the Protection of State Information Bill following rigorous debate in the House on Thursday.
The Bill was passed with a vote of 178 for it and 74 against it, with one abstention.
It will now be sent to president Jacob Zuma to be signed into law.
During debate in parliament today, opposition parties indicated that they would be taking up the matter in the Constitutional Court.
Murray Hunter of the lobby group, Right2Know, campaign, say they're also considering legal action on the grounds that the Bill is unconstitutional.
"We believe that the bill is unconstitutional. I think the bill is a wrong move at a time where we are seeing growing levels of secrecy across the country," he said.
"We are seeing whistle-blowers being targeted and I think we are seeing a government slowly closing itself off from the people. As a result the Right2Know Campaign is looking to seek legal action if our concerns are not addressed, if this bill is signed into law, and potentially undermining constitutional rights." said Hunter.
