Professor Steve Cornelius, a South African lawyer who was appointed to the tribunal earlier this year, sent a letter addressed directly to IAAF president Lord Sebastian Coe, and called the new rule 'fundamentally flawed'.

The rule has been widely criticized as targeting South African track star Caster Semenya directly, as it affects both her preferred events (800m and 1500m), and will force her to either suppress her testosterone levels with medication, or change her distances to 5km or 10km.

Cornelius, who didn't overtly object about Semenya's case, wrote to Coe: "Sadly, I cannot in good conscience continue to associate myself with an organization which insists on ostracizing certain individuals, all of them female, for no reason other than being what they were born to be.

"The adoption of the new eligibility regulations for female classification is based on the same kind of ideology that has led to some of the worst injustices and atrocities in the history of our planet.

"How the IAAF Council can, in the 21st Century, when we are meant to be more tolerant and aware of fundamental human rights, even contemplate these kinds of objectionable regulations, is a sad reflection on the fact that the antiquated views of the 'old' scandal-hit IAAF, still prevails and that your promises of reform have been empty indeed."

Semenya, for her part, has been defiant about the development, and had already said after the Commonwealth Games that she was looking to expand her events to include the 5000m and 10,000m, indicating she will likely not submit to the medication rule.

Meanwhile, Cornelius is one of a number of objectors since the rule was announced last week, with South Africa's Minister for Sports and Recreation, Tokozile Xasa quoted on IOL as saying: "We see this as a targeted approach by the IAAF.

"This new initiative comes after she (Semenya) broke records at the Commonwealth Games. It is also Africans that are participating in long-distance races, therefore we view it as a target.

"To compound the argument, she's also a woman, hence this becomes sexist. This should have come a long time ago, not only when she wins medals as a way to discourage her.

"We take this as very sexist, racial and homophobic."

Tennis legend Martina Navratilova lent her support as well, on Twitter, calling it a 'racist and sexist rule overall'.