The 31-year-old was forced to change distance because she has too high testosterone levels to participate in the favorite distance of 800 meters.
In 2018, the International Athletics Federation, World Athletics, introduced a rule prohibiting hyperandrogenic women from competing in distances from 400 up to one English mile.
The reason is that their high testosterone levels are judged to give them too great an advantage.
Semenya has taken his case to, among other things, the sports international arbitration court, Cas, without being heard.
She has also refused to undergo hormone therapy.