CAPE TOWN, May 3 (Xinhua) -- Athletics South Africa (ASA) will challenge the International Association of Athletics Federation's (IAAF) new rules for female runners with high natural testosterone levels, said an ASA statement issued on Thursday.

The IAAF regulated last week that from November 1, female runners in events from 400 metres to the mile must have a blood testosterone level of below 5 nanomoles per litre.

Those female with an elevated level must lower it through hormonal contraceptives for six months, and then maintain that lower level or compete in other women's events or men's events.

The approach replaces previous hyperandrogenism regulations which were suspended in 2015 by CAS, which must now be in line with the new rules.

The regulations could affect the future career of South African star Caster Semenya, a twice Olympic and three-time world champion in the 800 meters. Nobody knew Semenya when she won the 800m world title in 2009. She was then the subject of gender tests, but no results released so far.

"ASA has studied the new regulations issued by IAAF on the latest classification of female athletes," said a statement.

"Based on this consultation, we have now taken a decision that we will challenge the IAAF on these new regulations as we have found them to be skewed. As a member federation, we will engage the IAAF as our mother body and if they do not change their minds on this new rule after this engagement, we will proceed to the Court of Arbitration for Sport (CAS) for further assistance on the matter," the statement added.