The Senegalese official started his career as a judge and was President of the Dakar Court between 1976 and 1984.

He then held high-profile positions within the Senegalese judicial system before serving as the country's Sports Minister between 2002 and 2005.

Ndiaye was an IOC member from 2002 to 2008, and in charge of the Ethics Commission from 2007 to 2017.

He was also a member of the IOC Juridical Commission from 2002 to 2015.

In his ethics role, he dealt with two high-profile plagiarism cases involving IOC members and doctoral theses.

Former Hungarian President Pál Schmitt was issued a warning in 2013 and Dae-Sung Moon was suspended in 2016.

IOC President Thomas Bach led the tributes here in Tokyo while the Olympic flag will be flown at half-mast at Olympic House in Lausanne.

"Youssoupha Ndiaye was instrumental in implementing the complex reforms of the IOC Ethics Commission," Bach said.

"He was an outstanding chairman of the Commission, and his unfailing loyalty and guidance enabled the IOC to take key decisions and strengthen the credibility of the Olympic Movement. 

"Mr Ndiaye was a man of impeccable integrity with whom I shared many years on the Legal Affairs Commission. 

"Personally, I am losing a wise friend whose advice was always very valuable for me and the whole IOC."

Ndiaye was a keen footballer who won a gold medal with Saint-Louis at the Dakar Friendship Games in 1963.

He also served as President of the Senegalese Football Federation.

Ban Ki-moon, who replaced Ndiaye as Ethics Commission chair in September 2017, said: "Under Mr Ndiaye's guidance, the statutes and rules of procedure were considerably improved, enhancing the independence of the IOC Ethics Commission. 

"His wisdom was a valuable asset in reaching high standards of good governance within the Olympic Movement."