Vuna was involved in an altercation with team-mate Kurtley Beale following the Rebels' 64-7 loss in Durban prompting the club to take immediate action and send the pair home to Australia.
While Beale's fate is still being considered by Rebels' management, the club suspended Vuna for one game, ruling him out of Saturday's clash with the Cheetahs in Bloemfontein.
He will be available again for the Rebels' game against the Western Force on April 6.
"I am deeply sorry for the embarrassment this event has caused to the club and the people I love," Vuna said in a statement released by the club.
"During my time with the Melbourne Rebels I have turned my life around.
"The outcome of this incident in Durban is not consistent with the values of my family, my church and my football club.
"I apologise to the many loyal Rebel fans who have been an inspiration to me."
Vuna has also been advised to not partake in any social media activities.
- Sports & Recreation
- Kurtley Beale