The 27-year-old was sparring with Michael Zerafa on Saturday night in Melbourne when the incident occurred. He was said to have taken a body shot before walking to his corner of the ring and then collapsed.
Jake Ellis, his promoter and friend announced the tragic news in a heartfelt tribute on Facebook.
‘It is with great sadness and shock to announce that ‘The Fighting Cowboy’ Dwight Ritchie sadly passed away today doing what he loved,’ the post read.
‘Dwight will always be remembered by the boxing fraternity as one of the brightest talents in Australia whose fighting style embodied exactly how he lived.
‘RIP Cowboy you’ll be forever missed.’
Ritchie was helping Zerafa train for his upcoming rematch with Jeff Horn when the incident occurred, the Sydney Morning Herald reports.
The Australian boxer, who only lost twice in his 21-fight career was also preparing for his light-middleweight fight against Tommy Browne, 36, in December.