Caster Semenya has once again left it in the hands of a legal eagle renowned for defending the dignity of local sports stars to pursue a fresh challenge against the International Association of Athletics Federations (IAAF).

Semenya confirmed yesterday she had teamed up with lawyer Gregory Nott, 58, to confront the IAAF over its recently amended rule that compels women athletes to lower their natural testosterone levels. Nott - of international law firm Norton Rose Fulbright - previously won a legal battle against the IAAF to allow Semenya back to competition after she was subjected to a gender verification row in 2009.

In 2008, he also helped the now jailed Oscar Pistorius win his case to compete against able-bodied athletes on his artificial blades.

In a joint statement issued yesterday, Semenya and Nott outlined their intentions to file a legal case before the Court of Arbitration for Sport (CAS) in Lausanne, Switzerland.

"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," noted Nott, who also won a legal case for ultra-marathon runner Ludwick Mamabolo in 2012.

Mamabolo tested positive for doping but his case was won on the grounds that the SA Institute for Drug-Free Sport did not follow proper procedure and it was forced to hand the runner his Comrades Marathon title and prize monies.

With the latest case, Nott said his legal firm had the backing of "our colleagues in Canada" who represented Indian sprinter Dutee Chand in her successful challenge to the IAAF's 2011 hyperandrogenism regulations, which were suspended by the CAS and subsequently withdrawn by the IAAF.

Semenya, like all athletes, is entitled to compete the way she was born without being obliged to alter her body by any medical means, the statement said yesterday.

"Ms Semenya will today [yesterday] file the legal challenge to ensure, safeguard and protect the rights of all women."

Semenya was quoted as saying: "I am very upset that I have been pushed into the public spotlight again. I don't like talking about this new rule. I just want to run naturally, the way I was born. It is not fair that I am told I must change..."

The IAAF regulation comes into effect on November 1.