Kunavore died in Suva Private Hospital last night, although the cause of death remains undisclosed.
Kunavore was forced to retire from rugby in 2010 after suffering two major injuries to his arm and undergoing a cardiac operation.
"It is so sad to lose a fellow rugby player and at such a young age. Kunavore was a very gifted and talented player and our thoughts and prayers go out to his family, may he rest in peace," said Fiji Rugby Union's development manager Sale Sorovaki.
The winger spent five years at Toulouse, scoring 101 points in his 80 appearances for the club. He also won seven caps for Fiji, helping them to the quarter-finals of the 2007 World Cup.