The National Key Points Act will not be scrapped but amended, Police Minister Nathi Mthethwa said on Friday.

"It's the parts of the act which are not in line with the Constitution that are going to be repealed but the national key points as an act is here to stay," he said during a National Assembly debate on the relevance of the act.

Earlier Democratic Alliance (DA) parliamentary leader Lindiwe Mazibuko lambasted government for keeping the apartheid-era law on the statute books to hide corruption.

This included the controversial R206 million upgrade to President Jacob Zuma's private Nkandla residence in KwaZulu-Natal.

The DA's submission of a private member's bill to replace the existing law was opportunistic, Mthethwa said. A review of the act was already in full swing, and an advisory committee announced in May was at an advanced stage in its work.

"The committee has come back to report that the work is ongoing. We are going at end of November to be coming up with a reviewed policy on this matter."

The policy would then go through a public participation process early next year.

Mthethwa said although the act was drafted by the apartheid regime, it remained relevant given problems in South Africa and many other countries around the world.

"Risk in the 21st century results from [a] complex mix of man-made and naturally occurring threats and hazards, including terrorist attacks, accidents, natural disasters and other emergencies.

"Within this context, our critical infrastructure and key resources may be directly exposed to the event or indirectly exposed..."

Government's stance on the act came under attack from most opposition parties in the House, who wanted the act scrapped and replaced with a new law.

The parties claimed it was and would continue to be abused by members of Zuma's executive as an excuse not to answer questions on how public money was being spent.

"Perhaps it's because over time this government has come to favour secrecy over transparency. Perhaps it's because this government would rather hide the truth than hold its own to account," Mazibuko said.

She submitted a private member's bill to Parliament this week aimed at replacing the National Key Points Act.

"It is a bill that will not be left open to government abuse so that ministers can declare key points every time they wish to hide how much money they have spent on security upgrades," she said.

She was referring to the classification of reports on probes into the Nkandla upgrade.

"We cannot afford to let our government spend a cent more on cattle culverts, and helipads, and astroturfs for some when we should be spending money on creating jobs and improving education and delivering services to the millions of people who need them," Mazibuko said.

Congress of the People leader Mosiuoa Lekota backed the DA's attempt to correct the apartheid-era law, citing abuse of the law in its current form.

"What we are now seeing is that legislation used by the National Party then is being used to advance corruption because now public funds are being taken to put in and give inheritance to those who happened to have occupied an office for a while," Lekota said.

He questioned why the Waterkloof Air Force Base, one of the country's prime military installations, was not a key point, while Nkandla was.

"Nothing can be more ridiculous than the fact that we are faced here with an administration who are determined to enrich itself for the limited period of time that it is in power," Lekota said.

Inkatha Freedom Party MP Velaphi Ndlovu said the act had to be either overhauled or amended.

Freedom Front Plus MP Pieter Groenewald said the party would support a revised law, but only if it contained clear criteria for declaring a key point.

"You cannot deny it that there was massive misuse of this act to protect Nkandla. What threat is there for South Africa if there's an attack... who wants to attack Nkandla?" Groenewald asked.