Olympic medal-winning boxer Darren Sutherland was found dead at home by his manager on Monday.
The 27-year-old, who won bronze for Ireland at the 2008 Games in Beijing, was found hanged in his flat in Bromley, south London, by Frank Maloney.
In a statement, the boxing promoter said: "It is very sad and unexpected.
"At this sad time my thoughts are with Darren's family and I hope their privacy at this very difficult time will be respected by the media.
"It is a tragedy for Ireland and the world of boxing."
His death is not being treated as suspicious.
Irish Minister for Arts, Sport and Tourism Martin Cullen offered condolences to Sutherland's family.
"The death of Darren is a great personal loss to them and to his many friends," the minister said.
"The tremendous effort and determination of this young man brought immense pride to Ireland in Beijing in 2008 when he joined a very select group of men who have won an Olympic medal for Ireland.
"It takes work, effort, desire and dedication to be a champion - qualities Darren had in abundance."
Britain's Olympic middleweight champion James DeGale, who beat Sutherland in Beijing, spoke of his shock at the Irishman's death.
"It is very, very sad news - I just can't believe it," he said.
"He was a big part of my Olympic medal journey, and it is just terrible. I just do not know what to say except that he was a brilliant fighter, in fact an excellent fighter, and he was a gentleman outside the ring as well.
"He had an Olympic bronze medal, and his whole life to look forward to. He had a great future, and my heart goes out to everyone who knew him."
Sutherland was one of the leading lights on the Irish boxing scene in the four years before the games and regarded as one of the best talents coached under the Irish Sports Council's high performance unit.
Sutherland had trained as a boxer in his teens joining the famous Brendan Ingle gym in Sheffield before giving up the sport.
He returned while studying sports science at Dublin City University in 2004.
He made his professional debut last December in Dublin, winning by a knockout.
His stated goal was to win a world super-middleweight title.
"I want to go all the way," he said on the day he turned pro.
"There's no point starting out if you don't believe you can win a world title. That's where I want to go."
Sporting chiefs in Ireland, including those who worked closely with him in the high performance unit, were said to be deeply shocked by his death.
Under Maloney's guidance and based in London Sutherland was being fast-tracked to the top ranks of the pro-circuit.
Sutherland was also the focus of an Irish documentary film, Saviours, based around the amateur boxing club in north inner city Dublin, St Saviour's.
© Press Association