Aids campaigners say that South Africa's ruling African National Congress (ANC) will lose votes at next year's election unless it provides anti-retroviral drugs to help fight the spread of Aids.
Zackie Achmat (l) says the government is in denial
The issue has dominated the first national Aids conference, which ended on Wednesday in the east coast city of Durban.
"I am an African National Congress (ANC) member and I can tell you that the ANC will do itself enormous harm if it does not have a treatment plan in place by next year's election," said Zackie Achmat, chairman of South Africa's Aids lobby group Treatment Action Campaign (TAC).
"Aids has become a political issue, because everyone that is infected needs access to anti-Aids drugs," Mr Achmat said.
The United Nations agency that deals with Aids, UNAids estimates that five million South Africans are HIV positive in a population of 44m people.
Experts warn that South Africa is now entering a "death phase" and that mortality rates will rise rapidly.
President Mbeki has come under fire from Aids activists both locally and internationally because of his stated belief that factors other than HIV could lead to Aids.
They blame his Aids policies for the slow progress in the fight against the disease in South Africa.
His health minister has also been strongly criticised and was booed by delegates at the start of the conference.
"The reason why South Africa can not move forward is because President Thabo Mbeki and Manto Tshabalala-Msimang are HIV denialists," said Mr Achmat.
South African newspapers have also joined the fray, with the Die Burger newspaper calling for an end to what it describes as the government's "insanity" over Aids.
The Anglican Archbishop of Cape Town, Njongonkulu Ndungane, has also criticised the South African government approach to Aids, describing it as "a world disgrace as serious as apartheid".
The TAC organised demonstrations around the venue of the Aids conference and it has called on South Africans to embark on "a civil disobedience campaign" to pressure the government into adopting a national Aids treatment plan.
In response the government has urged "patriotic South Africans" to ignore the call.