Park, winner of the Olympic gold medal in the 400 metres freestyle at Beijing 2008, is contesting a controversial Korean Olympic Committee (KOC) ruling which forbids athletes from representing any national team for three-years after a doping suspension.

He was banned in 2014 after testing positive for the anabolic steroid testosterone and served an 18-month suspension from the sport.

A cutoff date of July 8 has been cited for a final decision.

"Mr Park seeks an urgent ruling that would potentially allow him to compete at the Rio 2016 Olympic Games," said a CAS statement today.

"In March 2015, the International Swimming Federation (FINA) imposed an 18-month period of ineligibility on Park Tae-hwan following a positive anti-doping control for testosterone.

"His ban started on September 3, 2014 and ended on March 2, 2016. KOC regulations prohibit an athlete from competing for the Korean national team for three years after the completion of a doping sanction.

"Accordingly, the KOC has announced that it will not select Park Tae-hwan for the Rio 2016 Olympic Games.

"Tae Hwan Park is challenging such announcement before the CAS and seeks an urgent ruling by July 8, 2016, the cut-off date for selection to the Korean national swimming team for the Rio 2016 Olympic Games."

Park, a two-time world champion who also claimed two silver medals at London 2012, has already appealed unsuccessfully to the KOC.

“The regulation for the selection of national team representatives was made with the aim of demanding a high level of morality of our national team athletes and considering the dignity required of a public figure," a KOC statement declared earlier this month.

"Doping is against the fair play spirit, a basic requirement of athletes, and we decided that a rigorous response was needed for educational purposes to young athletes."