Harding-Marlin holds dual citizenship with Canada and Saint Kitts and Nevis but represents the latter in international competitions.

The 29-year-old was not selected by the Saint Kitts and Nevis Olympic Committee (SKNOC) to compete for the Caribbean nation at Tokyo 2020 following a decision on July 12.

Harding-Marlin has now requested that the SKNOC nominate her for the women’s 100 metres backstroke at Tokyo 2020 for a universality quota place.

The system allows a smaller nations with no Olympic swimming qualifier to enter up to one male and one female athlete at the Games.

The Ad Hoc Division of the CAS is due to hear case between Harding-Marlin and the SKNOC and the International Swimming Federation.

The panel of arbitrators is expected to make a decision later today.

Sport's highest court opened an Ad Hoc Division to deal with legal disputes and an Anti-Doping Division at the Games here last Tuesday (July 13).

It is operating from temporary offices at the Japan International Dispute Resolution Centre, located in the same area as the Tokyo 2020 Organising Committee's headquarters.

Athletes and other parties wishing to register a case with either division would normally be granted an in-person hearing, but the CAS has said this will not be possible at Tokyo 2020 "due to the current sanitary measures in force in Tokyo during the period of the Games" so hearings are taking place via video. 

Harding-Marlin was born in Quebec in Canada, swimming for McGill University in Montreal before moving to Saint Kitts and Nevis in 2013, where she is a lawyer. 

She competed at the 2019 World Championships in Gwangju in South Korea where she finished 41st in the 50m backstroke and 85th in the 100m freestyle.

Swimming at Tokyo 2020 is scheduled to run from July 24 to August 1.