Long-serving International Olympic Committee member Nat Indrapana passed away yesterday after a long battle with cancer. He was 80.
Dr Nat died peacefully at Bangkok's Siriraj hospital, said Khunying Patama Leeswadtrakul, Thailand's other IOC member.
The IOC is deeply saddened by his death, its president Thomas Bach said.
In honour of Nat, who became IOC member in 1990, the Olympic flag at the organisation's headquarters in Lausanne is being flown at half-mast for three days.
"With the death of Nat Indrapana, the IOC loses a true gentleman of sports. With his outstanding gentleness he made many friends around the world, including me. Over the years of his membership, Nat contributed greatly to the Olympic Movement and the protection of its values. For this, he mobilised all his personal forces to serve the IOC even while fighting his serious disease. We will all miss him greatly," Bach said in a statement.
"The IOC expresses its deepest sympathy to his family."
With a strong academic background, Nat was a key figure in the development of sports in Thailand and Asia, holding numerous positions within sports organisations in his country and continent.
He was deputy minister of Thailand's Tourism and Sports Ministry, president of the Asian Trap and Skeet Shooting Federation, member of the Asian Games Federation and Olympic Council of Asia, vice president of the World Taekwondo Federation, and executive member of the National Olympic Committee of Thailand, among several other positions.
Patama said: "I am sure that following his long illness it is a blessing that he no longer suffered.
"Like many of you, Nat Indrapana was a man I admire dearly. Few people can be as productive as he was throughout his life."