The IAAF commissioned a gender test on the teenager after her performance levels improved remarkably in the build-up to the competition.
The leaked report that a gender verification test had found the 18 year-old to be a hermaphrodite with no womb was greeted with outrage in South Africa on Friday, with politicians, sports officials and Semenya's relatives decrying the teenager's public humiliation.
On Friday the IAAF attempted to diffuse the controversy by refusing to confirm the medical reports, insisting that it would make official comment until after the test results had been verified by a panel of scientific experts.
But the prospect of the teenager being disqualified from future female races drew a furious response from South African Sports Minister Makhenkesi Stofile, The Telegraph reports.
"I think it would be the third world war. We will go to the highest levels in contesting such a decision.She's a woman, she remains our heroine. We must protect her," he said.
Semenya was due to run in a 4km race at the national cross-country championships in Pretoria on Saturday, but was withdrawn by her coach Michael Seme on the grounds that she was "not feeling well".
The IAAF is expected to disqualify the South African from future events and advise her to have surgery because her condition carries grave health risks, The Daily Telegraph report claims.
A source closely involved with the IAAF tests said Semenya had internal testes-the male sexual organs, which produce testosterone.
"There certainly is evidence Semenya is a hermaphrodite. But the trouble is the IAAF now has the whole ANC and the whole of South Africa on their backs. Everything is going to have to be done absolutely by the book, no question of a challenge to the findings," the source said. (ANI)