Ikeys player Kyle Kriel punched a female Pukke student during a brawl with Pukke players in a Wimpy on Monday night.
UCT beat Pukke 39-33 in the Varsity Cup final in Potchefstroom and it's since emerged that Kriel was involved in an altercation after the game, and assaulted a female Pukke fan.
UCT has confirmed that it is looking into the matter.
'The Ikeys Rugby Club are aware of an allegation of assault made on social media against one of our players,' a UCT spokesman said in a statement on the club's website. 'We take the allegations seriously and will fully co-operate with an investigation.
'While the processes are underway the player accused is entitled to the presumption of innocence, but if the accusation is proven we will take appropriate action.'