Pone Fa'amausili and Hunter Paisami have been stood down pending the outcome of a police investigation into the alleged incident in the early hours of Sunday morning.
A Facebook post from a woman claiming to be the sister of the victim accused the pair of delivering a "king hit" to her brother from behind, causing him to lose consciousness and leaving him to bleed on the ground.
The Rebels confirmed Fa'amausili and Paisami had been stood down and that Rugby Australia had been made aware of the developments but did not offer any comment.
Fa'amausili has given a statement to police while Paisami is expected to do the same on Tuesday.
It comes just a week after a fight between departing Rebels players Amanaki Mafi and Lopeti Timani, the latter who was reportedly left fearing for his life as he was attacked by the Japanese international and his brother in Dunedin.
Mafi and Timani were fined $15,000 each for breaching team protocol by ignoring instructions from coach David Wessels not to go out drinking.
Fa'amausili and Paisami are both in their first seasons with the Super Rugby franchise.
Prop Fa'amausili, 21, has played only one match for the Rebels, an 11-minute cameo off the bench, but is signed to the club through to 2020.
Centre Paisami, 20, is yet to make a Super Rugby appearance and is on an extended squad contract.