Amenoni Nasilasila was sentenced to eight years in September for the 2018 rape of a young woman.
Last week, the 26-year-old Olympic gold medallist was reportedly seen training with the Namosi rugby teams in Suva.
But women's rights groups say the preferential treatment of high-profile prisoners has to stop.
Shamima Ali, of the Fiji Women's Crisis Centre, said the fact that Nasilasila's non-parole period was six years also highlighted the complete disregard by the department to allow him to participate in training with the Prisons and Namosi rugby teams.