"Rugby Australia and the Melbourne Rebels are aware of an incident involving Rebels players Amanaki Mafi and Lopeti Timani in Dunedin overnight," Rugby Australia said in a joint statement with the Rebels on Sunday.
"Both players remain in New Zealand with Mafi currently in Police custody following an altercation between the two players."
Japan international Mafi scored the first try for the Rebels on Saturday.
Fox Sports quoted a New Zealand Police spokeswoman saying "a man has been charged with injuring with intent to injure following an alleged assault in South Dunedin last night."
"The man is due to appear in the Dunedin District Court on the 16th July 2018," she said.
"The alleged victim... received moderate injuries following the incident. He did not require hospitalisation."
Rugby Australia and the Rebels said they understood no other players were involved in the incident.
"I am bitterly disappointed that an incident has occurred at the end of a season where we have taken pride in our on and off-field behaviour," Rebels chief executive Baden Stephenson said.
"We will respect the process and won't be making further comments until all investigations have taken place."
(Reporting by Sudipto Ganguly in Mumbai; editing by Amlan Chakraborty)
