World and Olympic champion Caster Semenya is to fight a move to compel some female athletes to medically lower naturally-occurring testosterone levels at the Court of Arbitration for Sport.

Lawyers representing the South African athlete have announced she has mounted a legal challenge to the International Association of Athletics Federations’ Eligibility Regulations for Female Classification in Lausanne.

The regulations, which were issued in April and are due to come into force on November 1, are designed to combat claims that women with higher levels of natural testosterone enjoy an unfair advantage in competition.

Gregory Nott, director of law firm Norton Rose Fulbright, said in a statement: “This is a landmark case concerning international human rights and discrimination against women athletes with major consequences for gender rights which are jealously protected by the South African Bill of Rights.

“We are honoured to represent Ms Semenya and advance a position that protects all affected women.”

Semenya’s legal representatives, led by Mr Nott, say she has filed her challenge “to ensure, safeguard and protect the rights of all women on the basis that the regulations are irrational, unjustifiable, and in violation of the IAAF Constitution (based in Monaco), the Olympic Charter, the laws of Monaco, the laws of jurisdictions in which international competitions are held, and of universally recognised human rights.”

The middle distance star, who has hyperandrogenism, a medical condition characterised by excessive levels of male sex hormones such as testosterone, has previously been asked to undergo gender testing.

Female athletes competing in events from 400m to the mile will be subject to the new rules.