Ng will announce his candidacy in Paris on Thursday, several officials with knowledge of the decision told The Associated Press on Tuesday. The officials spoke on condition of anonymity because the announcement hasn't been made yet.
Rogge, who succeeded Juan Antonio Samaranch in 2001, steps down Sept. 10 after 12 years in charge of the International Olympic Committee. The officials told the AP that Ng was in Lausanne, Switzerland, on Monday to notify Rogge of his decision.
German IOC Vice President Thomas Bach announced his candidacy last Thursday in Frankfurt. Richard Carrion of Puerto Rico, C.K. Wu of Taiwan and Sergei Bubka of Ukraine are among other likely contenders.
Ng, who chaired the organizing committee of the inaugural Youth Olympics in Singapore in 2010, has been an IOC member since 1998. He has served on the policy-making executive board since 2005 and as a vice president since 2009. He has been Singapore's ambassador to Norway since 2001 and is a former vice president of the international sailing federation.
The 64-year-old Ng will be seen as a candidate from Asia, a continent with growing economic, political and sports influence on the world stage.
Bach, a 59-year-old German lawyer, has been considered the front-runner in the IOC race.
The official deadline for candidacies is June 10, exactly three months before the election in Buenos Aires, Argentina.
An unofficial election campaign has been going on for months, with Bach, Ng and other prospective candidates traveling the world to attend various Olympic gatherings.
An announcement is likely by the end of the month from Carrion, a former executive board member who heads the IOC's finance and audit commissions.
Bubka is the former pole vault champion who still holds the world record. Wu is president of the international amateur boxing federation, AIBA.
On Tuesday, AIBA executive director Ho Kim sent a letter to federation members saying the executive committee recommended that Wu run for the IOC presidency.
Two Swiss members, Rene Fasel and Denis Oswald, have been weighing their options. Fasel is president of the International Ice Hockey Federation. Oswald is the former longtime head of the Association of Summer Olympic International Federations. It is unlikely both will run.
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