The Protection of Critical Infrastructure Bill, which has been red-flagged by information rights groups, on Tuesday passed its last parliamentary hurdle when it was adopted by the National Council of Provinces (NCOP).

The passage of the bill, which will replace the apartheid-era National Key Points Act, was not opposed by the opposition. 

It gives the police minister the discretion to declare certain installations critical infrastructure and prescribes how these are protected in the interest of national security.

The bill has been on the watch list of media activists, who have called for the inclusion of a public interest defence to shield whistle blowers and media who publish classified information to expose wrongdoing from prosecution.

They argued that like the National Key Points Act, which was famously invoked to cover up the lavish upgrades at former president Jacob Zuma's Nkandla home, its successor could be used to restrict critical media reporting.

Murray Hunter, the national coordinator of the Right 2 Know Campaign, drew a parallel with the shelved Protection of State Information Bill -- the so-called "Secrecy Bill", where activists lobbied in vain for years for the inclusion of a public interest defence.

"The NCOP has missed a massive opportunity not to repeat the mistakes it made with the Secrecy Bill, when they approved a bill so deeply problematic that it's gone unsigned for five years."

The bill will now go to Presidency Cyril Ramaphosa for signing into law.