Lawmakers drafting the Protection of Information Bill on Monday turned to the potentially fraught issue of prescribing a review process for all state secrets classified in past decades.

The African National Congress (ANC) proposed that organs of state be ordered to consider all their secret files and where they decide that classification was no longer necessary, hand them to the state security ministry to release.

"The person who classified must be responsible for declassifying," said Luwellyn Landers, the ANC MP leading the party's arguments on the ad hoc committee drafting the bill.

In the case of now-defunct apartheid era ministries, the decision would fall on the National Intelligence Agency and the Secret Service.

The process would be overseen by an independent review panel – a body agreed to by the ANC last month when it made a raft of concessions on the highly contentious bill.

Landers said the panel would conduct random sampling to see whether departments were behaving correctly.

Questions arose about what action should be provided for in law if a government department defied the panel's advice that the information had to be released.

Democratic Alliance (DA) justice and constitutional development spokesperson Dene Smuts warned that this might not be an uncommon occurrence.

She said "over-classification" was the norm under the existing policy document on state secrets -- the Minimum Information Security Standards (MISS) – and that it could be problematic to leave intelligence agents with a zeal for classification to decide whether thousands of files would be opened.

"The problem with the MISS is that it applied across the board... it was any damn thing, there were no criteria

"How confident must I be that the same people who classified, monitored, ordered and controlled are now going to declassify?

"How are we going to control what the spookery gets up to? We have to be careful about what they do not want to declassify. They have a different mindset."

Landers conceded that while there was expected to be little controversy over releasing apartheid-era secrets, this may not be the case with secret files dating from the democratic era.

"Where we may have a sense of discomfort is post-1996, perhaps," he said.

Lawmakers eventually neared agreement that the review panel be given greater powers than chapter nine institutions and be able to make legally binding recommendations.

Monday marked the first day of deliberations since the ANC's agreement last month to restrict the scope of the bill after almost a year of public pressure, and a Congress of South African Trade Unions (Cosatu) threat to approach the Constitutional Court if it were passed without major amendments.

The ANC chairperson of the ad hoc committee, Cecil Burgess, was at pains to point out that the promised concessions were still on the cards after several weeks of parliamentary recess.

"It is going to be in line with our Constitution. It is going to be very restricted," he said.

MPs later turned to an area in which the ANC lawmakers have refused to budge – the inclusion of a so-called public interest defence as protection for the media and whistle-blowers.

The ANC will go as far only as duplicating the public interest override clause contained in the Promotion of Access to Information Act, where it allows for declassification if the public interest outweighs reasons for non-disclosure.

Smuts cited a paper by University of the Witwatersrand academics Jonathan Klaaren and Iain Currie arguing that the "effectiveness of the public interest override is limited by unreasonably high threshold that it imposes" and renders it "largely nugatory and arguably unconstitutional".

The issue was one of those raised by Cosatu and is expected to generate more heated debate as lawmakers meet throughout for the rest of a week to work on the bill.

Meanwhile, government spokesperson Jimmy Manyi told reporters in Pretoria that he had been encouraged by the "robustness of discussions" on the proposed legislation.

Speaking at the Pretoria Press Club, Manyi rejected concerns that the legislation was a bid to rein in the media, but again called for greater media diversity.

"This government is pro a free media. It is a constitutional requirement, but the media must understand its freedom. It needs to be free from other interests."

Asked if he thought there was any media that was free from influence from "proxies" and other political parties, he said: "It is for you to make that call. We don't want to do that."