CAPE TOWN (Reuters) - Former President Nelson Mandela has repudiated the controversial position on AIDS web of his successor, Thabo Mbeki, saying HIV is the primary cause of the disease that threatens to kill 6 million South Africans.

In an interview published by Independent Group newspapers on Friday, Mandela, 82, said he would respect "the dominant opinion which prevails throughout the world" that HIV causes AIDS until he was shown conclusive and scientific proof this was wrong.

Mbeki, who succeeded Mandela in June last year, has taken the opposite view, saying he will not accept the link unless it is proved anew by an international panel he has appointed to test the link between human immunodeficiency virus, HIV, and the acquired immunodeficiency syndrome, AIDS.

Appearing to suggest that Mbeki should align himself with the scientific community, Mandela said: "I would like to be very careful because people in our positions, when you take a stand, you might find that established principles are undermined, sometimes without scientific backing."

Welfare Minister Zola Skweyiya told reporters earlier this month the AIDS pandemic would kill about 6 million South Africans over the next 10 years if it was left unchecked.

More than 10% of South Africans--about 4.2 million people--carry HIV and the disease is spreading in the country faster than anywhere else on earth.

Since Mbeki first voiced his doubts in the upper chamber of parliament last year, only one cabinet minister from the ruling African National Congress , Labour Minister Membathisi Mdladlana, has dared to say publicly that HIV causes AIDS.

Health Minister Manto Tshabalala-Msimang told a news conference last week she had never denied a link, but became angry when pressed to state that HIV did cause AIDS, saying: "You cannot put words into my mouth...I am not a schoolgirl."

Mbeki told parliament last week his strategy to fight AIDS was based on the "thesis" that HIV caused AIDS, but refused to say he accepted the link.

In a statement strongly contested by doctors, he told legislators that a virus could not cause a syndrome.

Asked in a recent interview with Time magazine whether he would acknowledge a link, Mbeki said: "This is precisely where the problem starts. No, I am saying that you cannot attribute immune deficiency solely and exclusively to a virus."AIDS activists charge that Mbeki's reluctance to acknowledge a link is undermining efforts to promote safe sex amongst young people and to help HIV-positive mothers protect their babies.

The powerful South African Congress of Trade Unions (Cosatu), Anglican Archbishop Njongonkulu Ndungane and opposition leaders have repeatedly urged Mbeki to abandon his scepticism and put out a strong message on the HIV-AIDS link.

Mandela has been careful to avoid criticising Mbeki, but in his interview with Daily News editor Kaizer Nyatsumba, he said his successor worked under great pressure and added "...now and again (he) must come under severe criticism."