History may be written by the victors, but who gets top billing? South Africa's ruling African National Congress, one of the most famous political movements in history, has been accused of "airbrushing people out" of the liberation past as it prepares to celebrate its centenary.

The ANC, the oldest liberation movement in Africa, turns 100 years old next Sunday, the cue for year-long commemorations costing 100m rand (£7.8m).

While no one questions the central role of Nelson Mandela and other ANC leaders in winning freedom from racial apartheid in 1994, rival political organisations and various commentators say the anniversary will be manipulated to sideline the contributions of others.

"The ANC are rewriting history," said Allister Sparks, a veteran journalist and analyst and the co-author of Tutu: The Authorised Portrait. "They're airbrushing people out. I don't know of a street named after Desmond Tutu, and he was effectively the leader [of the anti-apartheid movement] for 15 years. I'm not trying to belittle the ANC, but they didn't do it all."

The ANC was founded at a meeting of black activists and intellectuals in a Bloemfontein church in 1912. It resisted white minority rule, was banned in 1960 and launched an armed struggle a year later. After the arrest of Mandela and others, its leaders continued their work in exile and lobbied for international sanctions that ultimately helped topple the apartheid regime. Mandela was released in 1990, and when the first democratic, multiracial elections were held four years later the ANC won by a landslide.

Today visitors to South Africa could be forgiven for thinking the credit belongs to the ANC alone. Johannesburg, for example, has a Mandela House museum, Nelson Mandela Bridge, the Mandela Theatre and a six-metre-high bronze statue of Mandela in Nelson Mandela Square. But this narrative overlooks the role of others in events such as the Sharpeville massacre and the Soweto student uprising as well as that of churches, trade unions and giant personalities, including black nationalist leader Robert Sobukwe, liberal opposition MP Helen Suzman and Black Consciousness founder Steve Biko.

Archbishop Emeritus Tutu recently attacked the ANC for neglecting the influence of church leaders during the struggle. "The trouble is that the ANC on the whole reckons that the freedom we enjoy is due to them," he said. "Everyone else is just a sideline." Referring to a state-of-the-nation address by President Jacob Zuma, Tutu continued: "I sat in the audience and listened to this president paying tribute to all the people who had helped to bring about democracy in the country. This president did not mention a single religious leader." Church leaders had encouraged up to 30,000 people at a time to march against apartheid, he added. "There was a time when the people leading the struggle were religious leaders. Let the ANC know, they cannot airbrush us out."

There has also been criticism from the Pan Africanist Congress (PAC), a black nationalist movement that broke from the ANC in 1959. It organised the 1960 protest march in Sharpeville, where police fired on an unarmed crowd, killing 69, a defining moment in liberation history. But on the 50th anniversary of the massacre, ANC youth leader Julius Malema claimed that the memory of Sharpeville belonged to the ANC.

The PAC's forgotten role was the subject of further controversy last week when the ANC and the media were accused of ignoring the fact that the majority of political prisoners hanged by the apartheid government belonged to the party. Sam Ditshego, of the Pan Africanist Research Institute, wrote: "Many people are not aware that the first political prisoners on Robben Island were PAC members and that the longest-serving political prisoner on Robben Island was a PAC founding member, the late Jafta Masemola. PAC political prisoners were treated more harshly than ANC political prisoners on Robben Island. Please allow PAC members to tell our story. The media and the ANC are guilty of lying by omission."

PAC founder Sobukwe is given little tribute, apart from a brief description to tourists outside his prison on Robben Island. In South Africa's last general election, the ANC polled 65.9%, while the PAC received 0.27%.

The jamboree around the ANC's centenary contrasts sharply with the failure to mark modern South Africa's own centenary two years ago. Even the deputy president, Kgalema Motlanthe, admitted at the time that he was astonished by the "deafening silence" around the 100th anniversary of the Union of South Africa.

Opposition parties have raised concerns that public funds and other resources may be used for a party political event. The ANC has reportedly spent 10m rand of taxpayers' money to buy back the church where its founding fathers met in 1912 so that Zuma can light a "centenary flame" there.

Political activist Andile Mngxitama, co-editor of Biko Lives!, said the centenary would expose how the ANC marginalises rival groups. "They are going to play on the idea they were the sole liberator of our country. They're not going to acknowledge Black Consciousness, the Pan Africanist Congress, the independent voices of students. This is the last shot they have at maintaining a hegemony over society."

The ANC needs to trade on its heroic past to conceal its present failings, he added. "Our government lacks this little thing called black consciousness. If they had it, they would be building better houses, better schools and better transport. Instead they have affirmed the idea of black inferiority. History has been used as a cover-up for the failure to provide basic services to our people. I think it's a tragedy that history has been abused like this, to the point that children will laugh at it and spit at it."

The ANC denies that it is hijacking South Africa's struggle history. Jackson Mthembu, its national spokesperson, acknowledged that the party did not act alone and said Tutu and other leading figures have been invited to its celebrations. "We played a prominent part, no question about it, but that doesn't mean there were no Bikos."

But he added: "When you celebrate 100 years of the ANC, it's 100 years of the struggle in this country. You cannot include those who were not part of the ANC. It does not make sense. If we celebrated leaders who were not ANC, we would then be blamed for taking over the PAC. We expect the PAC to celebrate its leaders and we will be there. They can't blame another organisation because they don't have the capacity."