The ANC has dismissed as a distortion of facts, a National Press Club "Black Tuesday" protest campaign, to mark the National Assembly vote on the Protection of State Information Bill.

"The only result this unfortunate comparison and the planned campaign, in which people are urged to dress in black will achieve is to dilute the real history of the Black Wednesday and insult the victims of apartheid's barbaric laws," ANC Chief Whip Mathole Motshekga said on Monday.

The National Press Club (NPC) has asked people opposed to the bill to wear black clothing or a black ribbon or armband to express their opposition to the bill.

The National Assembly will vote on the draft law on Tuesday after more than a year of deliberations that have failed to ease fears that it will lead to excessive state secrecy and curtail media freedom.

On Friday, the ad hoc committee on the Protection of State Information Bill formally adopted a report rejecting all 123 amendments proposed by the Inkatha Freedom Party.

"Black Wednesday" was October 19 1977 when The World, Sunday World and Christian publication Pro Veritas, were banned and almost 20 people or organisations were declared banned by the apartheid government.

The campaign has been named "Black Tuesday" in reference both to this and to the day of the week on which the bill will be voted on in the National Assembly.

"Let's tell the government we are all opposed to censorship. It's crunch time. The nation needs to unite and stop this nonsense," NPC chairman Yusuf Abramjee said on its Facebook page.

If the bill is passed, the media will not be able to claim it acted in the pubic interest if it violated or was party to the violation of a law, or published classified information to substantiate a report on, for example, malpractice or corruption in government.

However, Motshekga said comparing the facts of Black Wednesday with the new draft legislation was "not only an irresponsible act of protest," but was also "gravely senseless".

"The reality of South Africa's vicious history should teach all of us never to campaign in a manner that trivialises the deep pain and suffering experienced by the majority of our people," he said.

The ANC's majority is expected to pass the bill comfortably on Tuesday, though all opposition parties plan to vote against it.

The bill then has to move through the National Council of Provinces before it can be signed into law.

If passed in its current form, it is likely to land up in the Constitutional Court.

ANC ally the Congress of SA Trade Unions, media groups and civil rights organisations have all threatened to take it on review, notably because of the absence of a public interest defence.

The Right 2 Know Campaign was organising six pickets around the country, including one at Parliament, to protest against the bill.

Motshekga said the government had no intention of banning, torturing or murdering journalists and that the rejection of a public interest defence was in line with international best practice on security in the United States, Canada and the United Kingdom.

"We believe this is blatantly insensitive and a distortion of history."

On Black Wednesday, editors Percy Qoboza and Aggrey Klaaste were taken to solitary confinement where they spent five months.

According to The Sowetan archive, journalists such as Mathatha Tsedu, Joe Tlholoe, who is now the Press Ombudsman; and Don Mattera were detained and after their jail stay were banned for five years.

Organisations banned included the Beyers Naude's Christian Institute and the Union of Black Journalists.

"Black Wednesday" followed the death in police detention of black consciousness activist Steve Biko, as well as a campaign to resist Bophutatswana becoming a "homeland" independent of South Africa.