Double Olympic champion Caster Semenya will be able to run in her favoured 800 metres event without medication to lower her testosterone levels until an appeal to the Swiss Federal Tribunal has been ruled on, her lawyers said on Monday.

The Court of Arbitration for Sport (CAS) had ruled the International Association of Athletics Federations regulations were necessary for XY chromosome athletes with differences in sexual development (DSDs) competing in events ranging from 400 metres to a mile.

"The Federal Supreme Court of Switzerland has ordered the IAAF to immediately suspend the implementation of the eligibility regulations against Caster Semenya, allowing her to compete without restriction in the female category while her appeal is pending," a statement from Semenya's lawyers said.

No timeframe has been given for when a final ruling might be made, but the IAAF will make further submissions to the court, the statement said.

"The Swiss Supreme Court has granted welcome temporary protection to Caster Semenya. This is an important case that will have fundamental implications for the human rights of female athletes," added Dorothee Schramm of Sidley Austin LLP, Swiss counsel for Semenya.

The IAAF said it had not yet been notified of the suspension.

"We have received no information from the Swiss Federal Court so we cannot comment at this stage," an IAAF spokesperson said.

Speaking through her lawyers, Semenya said she remains hopeful of her appeal being successful.

"I am thankful to the Swiss judges for this decision. I hope that following my appeal I will once again be able to run free," she said.

The temporary suspension of the rules comes after the 28-year-old Semenya last week filed an appeal to the Swiss Supreme Court asking for the testosterone limits in female events to be removed completely.

That full appeal will be heard by a panel of Swiss federal judges.

The IAAF's testosterone limits apply to female athletes with conditions known as "differences of sex development" (DSD).

The IAAF says the athletes affected have levels of testosterone in the male range and gain an athletic advantage from their elevated levels of the muscle-building hormone. To be eligible to compete in certain events, the athletes must lower their testosterone to below a point specified by the IAAF through medication or surgery.

The CAS verdict is proving to be highly controversial, with many high-profile current and former athletes lining up on both sides of the debate.

Semenya and at least one other athlete affected by the regulations, Olympic 800 metres bronze medalist Margaret Wambui, have refused to take any medication to lower their hormone levels.